Setting

Design: The purpose of this experiment is to investigate the amount of Superplasticizer used in making concrete dependent on the overall age(in days) of the concrete mixture. The analysis uses the strength (in MPa) and amount of water utilized to make the the mixture as the explanatory variable (cannot be controlled).Essentially we are trying to compare the different amounts of Superplasticizer used(kg in m^3 mixture) and their effect on the overall age of the mixture. Now strength and water used (superplasticizer are fluids that reduce moisture usage and still provide strength to th mixture) are known to be affected by the proportion of Superplasticizer used in making the concrete mixture but we want to see its effect on the age of the mixture (in days).For this anlysis we use analysis of covariance (ANCOVA) technique.

Data Summary and Exploratory data analysis

The data is a subset of a large dataset involving strength of materials. We consider only the composition and strength of concrete mixture. Independent variables are the various constituents (7 in this case)that are used to make the concrete mixture used in a variety of construction applications (buildings and bridges).

Data Type: multivariate

Abstract: Concrete is the most important material in civil engineering. The concrete compressive strength is a highly nonlinear function of age and ingredients. These ingredients include cement, blast furnace slag, fly ash, water, superplasticizer, coarse aggregate, and fine aggregate.

Source:See References

Data Characteristics(Randomization scheme):

The actual concrete compressive strength (MPa) for a given mixture under a specific age (days) was determined from laboratory. Data is in raw form (not scaled).

Summary Statistics:

Number of instances (observations): 1030 Number of Attributes: 9 Attribute breakdown: 8 quantitative input variables, and 1 quantitative output variable Missing Attribute Values: None

A summmary of the given dataset and exploratory data analysis is presented here

# Selecting the data file from the local machine

dataf<- (read.csv(file.choose(), header=T))

summary(dataf)
##      Cement      Blast.Furnace.Slag    Fly.Ash           Water      
##  Min.   :102.0   Min.   :  0.0      Min.   :  0.00   Min.   :121.8  
##  1st Qu.:192.4   1st Qu.:  0.0      1st Qu.:  0.00   1st Qu.:164.9  
##  Median :272.9   Median : 22.0      Median :  0.00   Median :185.0  
##  Mean   :281.2   Mean   : 73.9      Mean   : 54.19   Mean   :181.6  
##  3rd Qu.:350.0   3rd Qu.:142.9      3rd Qu.:118.30   3rd Qu.:192.0  
##  Max.   :540.0   Max.   :359.4      Max.   :200.10   Max.   :247.0  
##  Superplasticizer Coarse.Aggregate Fine.Aggregate       Age        
##  Min.   : 0.000   Min.   : 801.0   Min.   :594.0   Min.   :  1.00  
##  1st Qu.: 0.000   1st Qu.: 932.0   1st Qu.:731.0   1st Qu.:  7.00  
##  Median : 6.400   Median : 968.0   Median :779.5   Median : 28.00  
##  Mean   : 6.205   Mean   : 972.9   Mean   :773.6   Mean   : 45.66  
##  3rd Qu.:10.200   3rd Qu.:1029.4   3rd Qu.:824.0   3rd Qu.: 56.00  
##  Max.   :32.200   Max.   :1145.0   Max.   :992.6   Max.   :365.00  
##     strength    
##  Min.   : 2.33  
##  1st Qu.:23.71  
##  Median :34.45  
##  Mean   :35.82  
##  3rd Qu.:46.13  
##  Max.   :82.60
# Graphical representation

plot(dataf)

plot(dataf$Age~dataf$strength,pch=as.character(dataf$Superplasticizer),xlab="Strength in Mpa", ylab="Superplasticizer in kg/m^3")

plot(dataf$Age~dataf$Water,pch=as.character(dataf$Superplasticizer),xlab="Water in m^3", ylab="Superplasticizer in kg/m^3")

#par(mfrow=c(1,1))

#Create histogram 

hist(dataf$Superplasticizer, xlim=c(0,50), ylab = "Superplasticizer in kg/m^3")

hist(dataf$strength, xlim=c(0,100), ylab = "Strength in MPa")

hist(dataf$Water, xlim=c(0,400), ylab = "Strength in MPa")

#Boxplots
boxplot(dataf$Age~dataf$Superplasticizer,data=dataf, xlab="Amount of Sperplasticizer in kg/m^3", ylab="Age in days")
title("Boxplot of Age variability due to Superplasticizer")

As is evident from the scatter above plot that there is no clear relationship between the amount of superplasticizer used and the age of the mixture and that is why we conduct this analysis. Also, the boxplot depicts variability of different superplasticizer quantities with that of age therefore we formulate our null hypothesis as:

There is no effect of the amount of superplasticizer used on the age of the concrete mixture.

Factors and Levels

As mentioned before, the dataset has 7 factors with multiple levels.Response variable is the age of the concrete mixture.

# Defining the factors

dataf$Superplasticizer=as.factor(dataf$Superplasticizer)

Testing-Analysis of covariance (ANCOVA)

ANCOVA can be used to increase statistical power i.e. the ability to find a significant difference between groups when one exists by reducing the within-group variance.The assumptions that undelie the analysis are: normality,homogeniety of variances,homogeneity of regression slopes, linearity of regression, Independence of error terms.

datafaov=lm(Age~strength+Water+Superplasticizer,data=dataf)
anova(datafaov)
## Analysis of Variance Table
## 
## Response: Age
##                   Df  Sum Sq Mean Sq  F value  Pr(>F)    
## strength           1  444112  444112 158.1655 < 2e-16 ***
## Water              1  623166  623166 221.9337 < 2e-16 ***
## Superplasticizer 110  464044    4219   1.5024 0.00117 ** 
## Residuals        917 2574839    2808                     
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Conclusion: From the results we can reject the null hypothesis as there is a clear effect of variability in superplasticizer weight on the overall age of the concrete mixture based on the small p-value (less than 0.05) that cannot be attributed to randomization alone.

Estimation of Parameters

Parameter estimation involves calculation of contrasts. We calculate the estimates and the confidence intervals for the co-efficients in the linear model.Basically, the contrast specifies how the levels of the factors will be coded into a family of numeric dummy variables for fitting the model.

contrasts(dataf$Superplasticizer)=contr.sum 
datafaov=lm(Age~strength+Water+Superplasticizer,data=dataf) 
summary(datafaov)
## 
## Call:
## lm(formula = Age ~ strength + Water + Superplasticizer, data = dataf)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -122.269  -23.357   -5.936   13.389  313.347 
## 
## Coefficients:
##                      Estimate Std. Error t value Pr(>|t|)    
## (Intercept)         -289.5627    23.5746 -12.283  < 2e-16 ***
## strength               2.1991     0.1201  18.314  < 2e-16 ***
## Water                  1.3681     0.1328  10.304  < 2e-16 ***
## Superplasticizer1     22.0172     5.3445   4.120 4.14e-05 ***
## Superplasticizer2     -7.3288    26.9405  -0.272 0.785656    
## Superplasticizer3     -2.5652    52.8234  -0.049 0.961280    
## Superplasticizer4     24.4159    52.6294   0.464 0.642814    
## Superplasticizer5     24.1423    52.6292   0.459 0.646541    
## Superplasticizer6    -60.0775    37.5038  -1.602 0.109521    
## Superplasticizer7    -26.6360    21.8525  -1.219 0.223197    
## Superplasticizer8    -13.8185    52.7090  -0.262 0.793252    
## Superplasticizer9    -14.9696    30.5654  -0.490 0.624424    
## Superplasticizer10    -1.1187    23.7214  -0.047 0.962396    
## Superplasticizer11   -67.4538    19.3371  -3.488 0.000509 ***
## Superplasticizer12   -22.5681    52.9144  -0.427 0.669842    
## Superplasticizer13    45.6366    23.8182   1.916 0.055671 .  
## Superplasticizer14    24.3313    17.0482   1.427 0.153861    
## Superplasticizer15     1.0877    16.5112   0.066 0.947493    
## Superplasticizer16   -29.0106    26.5454  -1.093 0.274739    
## Superplasticizer17   -40.8177    37.3260  -1.094 0.274442    
## Superplasticizer18     5.2697    23.8697   0.221 0.825323    
## Superplasticizer19    -1.3761    16.2467  -0.085 0.932517    
## Superplasticizer20    51.4019    15.6793   3.278 0.001083 ** 
## Superplasticizer21    -5.5348    16.4460  -0.337 0.736539    
## Superplasticizer22   -43.0940    30.5473  -1.411 0.158663    
## Superplasticizer23   -38.4152    13.8525  -2.773 0.005664 ** 
## Superplasticizer24    -1.0147    20.3321  -0.050 0.960207    
## Superplasticizer25   -48.0230    52.8862  -0.908 0.364094    
## Superplasticizer26   -15.1272    52.7514  -0.287 0.774358    
## Superplasticizer27     1.5156    21.7797   0.070 0.944535    
## Superplasticizer28     9.6356    21.6880   0.444 0.656945    
## Superplasticizer29   -89.1013    52.7613  -1.689 0.091605 .  
## Superplasticizer30     9.4512    16.1890   0.584 0.559496    
## Superplasticizer31   -15.2912    21.7170  -0.704 0.481542    
## Superplasticizer32   -17.2327    12.6847  -1.359 0.174625    
## Superplasticizer33    15.6126    52.6582   0.296 0.766924    
## Superplasticizer34    -2.7002    52.6143  -0.051 0.959081    
## Superplasticizer35   -36.6054    52.7335  -0.694 0.487758    
## Superplasticizer36    33.3033    16.2089   2.055 0.040197 *  
## Superplasticizer37    24.8116    21.6996   1.143 0.253165    
## Superplasticizer38    27.3433    13.5572   2.017 0.043999 *  
## Superplasticizer39    20.9030    21.6969   0.963 0.335596    
## Superplasticizer40    -0.2388    10.6645  -0.022 0.982142    
## Superplasticizer41   -13.1981    21.6993  -0.608 0.543188    
## Superplasticizer42    25.7777    21.7010   1.188 0.235197    
## Superplasticizer43    -8.0381    37.2764  -0.216 0.829321    
## Superplasticizer44    -8.7153    52.6731  -0.165 0.868617    
## Superplasticizer45   -36.8547    21.7284  -1.696 0.090196 .  
## Superplasticizer46   -28.9974    21.7316  -1.334 0.182423    
## Superplasticizer47    42.7881    23.7915   1.798 0.072432 .  
## Superplasticizer48    -2.6184    52.7994  -0.050 0.960458    
## Superplasticizer49   -29.6607    13.6127  -2.179 0.029593 *  
## Superplasticizer50   -20.1428    13.6726  -1.473 0.141035    
## Superplasticizer51    17.7679    26.7337   0.665 0.506457    
## Superplasticizer52   -23.3726    37.3445  -0.626 0.531559    
## Superplasticizer53    17.9938    23.7151   0.759 0.448199    
## Superplasticizer54   -16.9631    14.9649  -1.134 0.257290    
## Superplasticizer55    10.1927    21.7744   0.468 0.639821    
## Superplasticizer56    13.5013    23.7065   0.570 0.569144    
## Superplasticizer57   -16.8240    52.7081  -0.319 0.749654    
## Superplasticizer58    31.5098    13.5782   2.321 0.020526 *  
## Superplasticizer59   -11.5448    14.0783  -0.820 0.412405    
## Superplasticizer60   -20.5438    20.1360  -1.020 0.307878    
## Superplasticizer61    35.2176    23.8306   1.478 0.139797    
## Superplasticizer62   -47.3300    21.7915  -2.172 0.030115 *  
## Superplasticizer63     7.8628    16.9343   0.464 0.642532    
## Superplasticizer64   -54.4327    53.0071  -1.027 0.304741    
## Superplasticizer65   -25.2020    52.7253  -0.478 0.632773    
## Superplasticizer66   -11.2665    52.6182  -0.214 0.830502    
## Superplasticizer67    32.9863    21.7238   1.518 0.129249    
## Superplasticizer68    -4.1067    17.9753  -0.228 0.819338    
## Superplasticizer69   -19.2956    14.7647  -1.307 0.191584    
## Superplasticizer70   -44.5140    20.2558  -2.198 0.028228 *  
## Superplasticizer71    -2.7906    17.2602  -0.162 0.871597    
## Superplasticizer72    13.6480    18.8627   0.724 0.469530    
## Superplasticizer73   -12.7183    24.1315  -0.527 0.598291    
## Superplasticizer74   -14.0784    52.6243  -0.268 0.789123    
## Superplasticizer75   -20.5019     9.4886  -2.161 0.030978 *  
## Superplasticizer76    26.9927    16.2668   1.659 0.097383 .  
## Superplasticizer77    13.2872    23.7733   0.559 0.576358    
## Superplasticizer78    24.2746    21.9983   1.103 0.270111    
## Superplasticizer79    23.5277    17.9397   1.311 0.190021    
## Superplasticizer80    10.9178    23.8064   0.459 0.646626    
## Superplasticizer81     0.3957    52.6135   0.008 0.994001    
## Superplasticizer82    -2.7550    52.7843  -0.052 0.958386    
## Superplasticizer83    51.6679    23.9783   2.155 0.031439 *  
## Superplasticizer84    20.5216    37.3202   0.550 0.582536    
## Superplasticizer85   -16.4656    52.6263  -0.313 0.754445    
## Superplasticizer86    35.4620    21.7679   1.629 0.103635    
## Superplasticizer87     9.8014    26.4752   0.370 0.711311    
## Superplasticizer88    22.3592    52.7476   0.424 0.671745    
## Superplasticizer89     6.9728    26.5436   0.263 0.792845    
## Superplasticizer90    27.8106    23.9930   1.159 0.246712    
## Superplasticizer91     5.4829    17.9651   0.305 0.760285    
## Superplasticizer92    26.3621    26.5429   0.993 0.320880    
## Superplasticizer93   -38.4971    52.6548  -0.731 0.464891    
## Superplasticizer94    59.8992    52.7031   1.137 0.256027    
## Superplasticizer95    10.7604    23.8710   0.451 0.652260    
## Superplasticizer96    60.7082    37.3980   1.623 0.104869    
## Superplasticizer97    61.7688    52.7047   1.172 0.241510    
## Superplasticizer98    -3.2463    14.3155  -0.227 0.820654    
## Superplasticizer99    26.0290    37.3067   0.698 0.485540    
## Superplasticizer100   37.6368    37.3261   1.008 0.313564    
## Superplasticizer101    8.4663    52.6157   0.161 0.872201    
## Superplasticizer102   -2.1810    23.9694  -0.091 0.927520    
## Superplasticizer103   -1.2975    52.6184  -0.025 0.980333    
## Superplasticizer104   -1.5711    52.6188  -0.030 0.976187    
## Superplasticizer105  -20.7603    52.6887  -0.394 0.693660    
## Superplasticizer106  -33.2931    52.6558  -0.632 0.527362    
## Superplasticizer107  -15.1528    22.0868  -0.686 0.492851    
## Superplasticizer108    3.9435    52.6144   0.075 0.940270    
## Superplasticizer109   41.6002    24.5514   1.694 0.090526 .  
## Superplasticizer110   17.0664    24.1327   0.707 0.479627    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 52.99 on 917 degrees of freedom
## Multiple R-squared:  0.3729, Adjusted R-squared:  0.2963 
## F-statistic: 4.869 on 112 and 917 DF,  p-value: < 2.2e-16
confint(datafaov)
##                            2.5 %      97.5 %
## (Intercept)         -335.8291601 -243.296224
## strength               1.9634786    2.434811
## Water                  1.1075152    1.628693
## Superplasticizer1     11.5281957   32.506104
## Superplasticizer2    -60.2009998   45.543454
## Superplasticizer3   -106.2339111  101.103597
## Superplasticizer4    -78.8720819  127.703881
## Superplasticizer5    -79.1454597  127.430018
## Superplasticizer6   -133.6806905   13.525659
## Superplasticizer7    -69.5227958   16.250794
## Superplasticizer8   -117.2628746   89.625783
## Superplasticizer9    -74.9557779   45.016670
## Superplasticizer10   -47.6732964   45.435920
## Superplasticizer11  -105.4038795  -29.503766
## Superplasticizer12  -126.4154259   81.279214
## Superplasticizer13    -1.1078737   92.381126
## Superplasticizer14    -9.1266949   57.789307
## Superplasticizer15   -31.3165224   33.491835
## Superplasticizer16   -81.1073943   23.086162
## Superplasticizer17  -114.0720496   32.436677
## Superplasticizer18   -41.5759877   52.115301
## Superplasticizer19   -33.2610493   30.508829
## Superplasticizer20    20.6304740   82.173316
## Superplasticizer21   -37.8108381   26.741334
## Superplasticizer22  -103.0447160   16.856691
## Superplasticizer23   -65.6015863  -11.228848
## Superplasticizer24   -40.9175706   38.888103
## Superplasticizer25  -151.8150829   55.769145
## Superplasticizer26  -118.6546029   88.400257
## Superplasticizer27   -41.2281654   44.259461
## Superplasticizer28   -32.9283626   52.199474
## Superplasticizer29  -192.6480937   14.445553
## Superplasticizer30   -22.3205753   41.222932
## Superplasticizer31   -57.9120380   27.329647
## Superplasticizer32   -42.1270415    7.661675
## Superplasticizer33   -87.7319946  118.957099
## Superplasticizer34  -105.9585642  100.558090
## Superplasticizer35  -140.0977229   66.886901
## Superplasticizer36     1.4925020   65.114176
## Superplasticizer37   -17.7749669   67.398214
## Superplasticizer38     0.7365212   53.950027
## Superplasticizer39   -21.6782870   63.484240
## Superplasticizer40   -21.1684210   20.690877
## Superplasticizer41   -55.7841301   29.387943
## Superplasticizer42   -16.8116490   68.367054
## Superplasticizer43   -81.1949524   65.118814
## Superplasticizer44  -112.0891222   94.658423
## Superplasticizer45   -79.4977715    5.788380
## Superplasticizer46   -71.6468636   13.652058
## Superplasticizer47    -3.9039533   89.480240
## Superplasticizer48  -106.2402279  101.003336
## Superplasticizer49   -56.3764050   -2.944991
## Superplasticizer50   -46.9760503    6.690472
## Superplasticizer51   -34.6984279   70.234223
## Superplasticizer52   -96.6632542   49.917955
## Superplasticizer53   -28.5484721   64.536046
## Superplasticizer54   -46.3324989   12.406328
## Superplasticizer55   -32.5408120   52.926245
## Superplasticizer56   -33.0239830   60.026506
## Superplasticizer57  -120.2665419   86.618606
## Superplasticizer58     4.8619420   58.157706
## Superplasticizer59   -39.1743313   16.084656
## Superplasticizer60   -60.0617319   18.974164
## Superplasticizer61   -11.5513376   81.986438
## Superplasticizer62   -90.0970140   -4.562996
## Superplasticizer63   -25.3715583   41.097258
## Superplasticizer64  -158.4620266   49.596622
## Superplasticizer65  -128.6782340   78.274179
## Superplasticizer66  -114.5326992   91.999618
## Superplasticizer67    -9.6478979   75.620468
## Superplasticizer68   -39.3842393   31.170875
## Superplasticizer69   -48.2721977    9.680976
## Superplasticizer70   -84.2671567   -4.760881
## Superplasticizer71   -36.6645878   31.083478
## Superplasticizer72   -23.3711061   50.667153
## Superplasticizer73   -60.0777426   34.641054
## Superplasticizer74  -117.3565734   89.199680
## Superplasticizer75   -39.1238175   -1.880044
## Superplasticizer76    -4.9318466   58.917207
## Superplasticizer77   -33.3691832   59.943561
## Superplasticizer78   -18.8983177   67.447430
## Superplasticizer79   -11.6799111   58.735376
## Superplasticizer80   -35.8036538   57.639221
## Superplasticizer81  -102.8610797  103.652470
## Superplasticizer82  -106.3470056  100.837021
## Superplasticizer83     4.6091440   98.726632
## Superplasticizer84   -52.7213076   93.764593
## Superplasticizer85  -119.7476313   86.816504
## Superplasticizer86    -7.2585460   78.182643
## Superplasticizer87   -42.1575730   61.760377
## Superplasticizer88   -81.1608265  125.879309
## Superplasticizer89   -45.1203930   59.066073
## Superplasticizer90   -19.2770094   74.898287
## Superplasticizer91   -29.7745408   40.740355
## Superplasticizer92   -25.7297871   78.454007
## Superplasticizer93  -141.8349411   64.840769
## Superplasticizer94   -43.5334264  163.331900
## Superplasticizer95   -36.0877877   57.608567
## Superplasticizer96   -12.6873620  134.103750
## Superplasticizer97   -41.6669980  165.204560
## Superplasticizer98   -31.3412523   24.848634
## Superplasticizer99   -47.1874635   99.245370
## Superplasticizer100  -35.6176531  110.891349
## Superplasticizer101  -94.7947610  111.727419
## Superplasticizer102  -49.2223137   44.860339
## Superplasticizer103 -104.5638648  101.968939
## Superplasticizer104 -104.8382481  101.696080
## Superplasticizer105 -124.1647470   82.644225
## Superplasticizer106 -136.6329105   70.046684
## Superplasticizer107  -58.4994793   28.193806
## Superplasticizer108  -99.3151587  107.202153
## Superplasticizer109   -6.5832477   89.783578
## Superplasticizer110  -30.2953019   64.428173

So from our results we can see that the value of µ, beta, alpha1, alpha2 are -289.5,2.2,1.3,22.7.Essentially if contrasts used here are changed, the model will be the same in terms of the underlying probability distributions allowed. Only the parameters will be different. The fitted values will stay the same as well. So once we have the value of the parameters for one choice of contrasts, it is easy to estimate the value of the parameters for another choice of contrasts.

Diagnostics/Model Adequacy Checking

Model adequacy checking is done to test the validity of ANCOVA given the numerous assumptions it is based on.

The shapiro test evaluates the Null hypothesis such that “the samples come from a Normal distribution” against the alternative hypothesis “the samples do not come from a Normal distribution”.

The Q-Q Norm plots also test the normality of the sample. The scatter plots of the residuals and the fitted model will check the distribution of the model over the entire dynamic range.

We also fit a model with different slopes for each factor level.

# Shapiro Test

shapiro.test(dataf$Age)
## 
##  Shapiro-Wilk normality test
## 
## data:  dataf$Age
## W = 0.5907, p-value < 2.2e-16
#Plots for checking normality

qqnorm(residuals(datafaov)) 
qqline(residuals(datafaov))

plot(fitted(datafaov),residuals(datafaov))

# Fit a model with different slopes for each factor level

aovdatafnew=lm(Age~Superplasticizer*Water*strength,data=dataf) 
summary(aovdatafnew)
## 
## Call:
## lm(formula = Age ~ Superplasticizer * Water * strength, data = dataf)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -172.93  -13.99    0.00    8.58  320.43 
## 
## Coefficients: (167 not defined because of singularities)
##                                      Estimate Std. Error t value Pr(>|t|)
## (Intercept)                        -4.486e+02  2.911e+05  -0.002    0.999
## Superplasticizer1                   6.716e+02  2.911e+05   0.002    0.998
## Superplasticizer2                  -5.757e+01  1.519e+05   0.000    1.000
## Superplasticizer3                   1.453e+03  3.134e+06   0.000    1.000
## Superplasticizer4                  -1.744e+01  2.736e+04  -0.001    0.999
## Superplasticizer5                  -1.790e+01  2.744e+04  -0.001    0.999
## Superplasticizer6                   1.075e+02  5.762e+04   0.002    0.999
## Superplasticizer7                   4.766e+02  2.911e+05   0.002    0.999
## Superplasticizer8                  -8.155e+01  3.096e+04  -0.003    0.998
## Superplasticizer9                   4.766e+02  8.897e+04   0.005    0.996
## Superplasticizer10                 -3.040e+01  9.590e+04   0.000    1.000
## Superplasticizer11                  2.187e+02  2.911e+05   0.001    0.999
## Superplasticizer12                 -1.045e+02  1.910e+04  -0.005    0.996
## Superplasticizer13                 -2.519e+01  4.656e+04  -0.001    1.000
## Superplasticizer14                  3.912e+02  2.911e+05   0.001    0.999
## Superplasticizer15                  2.771e+03  2.911e+05   0.010    0.992
## Superplasticizer16                  4.764e+02  4.179e+06   0.000    1.000
## Superplasticizer17                 -9.783e+02  4.126e+05  -0.002    0.998
## Superplasticizer18                 -2.048e+01  1.214e+05   0.000    1.000
## Superplasticizer19                  9.517e+01  2.911e+05   0.000    1.000
## Superplasticizer20                  4.022e+02  2.911e+05   0.001    0.999
## Superplasticizer21                 -1.282e+03  2.911e+05  -0.004    0.996
## Superplasticizer22                  4.766e+02  2.605e+05   0.002    0.999
## Superplasticizer23                  4.766e+02  2.911e+05   0.002    0.999
## Superplasticizer24                  2.034e+03  2.912e+05   0.007    0.994
## Superplasticizer25                 -1.395e+02  1.668e+04  -0.008    0.993
## Superplasticizer26                 -8.328e+01  3.978e+04  -0.002    0.998
## Superplasticizer27                 -7.496e+02  1.829e+05  -0.004    0.997
## Superplasticizer28                  3.432e+02  6.475e+04   0.005    0.996
## Superplasticizer29                 -2.149e+02  8.829e+04  -0.002    0.998
## Superplasticizer30                 -2.347e+02  2.911e+05  -0.001    0.999
## Superplasticizer31                  3.124e+03  3.678e+05   0.008    0.993
## Superplasticizer32                  3.670e+02  2.911e+05   0.001    0.999
## Superplasticizer33                 -3.137e+01  4.107e+04  -0.001    0.999
## Superplasticizer34                 -6.563e+01  7.490e+03  -0.009    0.993
## Superplasticizer35                 -1.211e+02  8.124e+03  -0.015    0.988
## Superplasticizer36                 -7.470e+02  2.911e+05  -0.003    0.998
## Superplasticizer37                 -1.880e+03  2.888e+05  -0.007    0.995
## Superplasticizer38                  1.016e+02  2.911e+05   0.000    1.000
## Superplasticizer39                  4.347e+01  1.637e+05   0.000    1.000
## Superplasticizer40                  4.766e+02  2.911e+05   0.002    0.999
## Superplasticizer41                  7.961e+02  3.415e+05   0.002    0.998
## Superplasticizer42                 -3.118e+02  1.583e+05  -0.002    0.998
## Superplasticizer43                  1.587e+02  5.199e+04   0.003    0.998
## Superplasticizer44                 -7.322e+01  2.711e+04  -0.003    0.998
## Superplasticizer45                 -5.094e+02  2.911e+05  -0.002    0.999
## Superplasticizer46                  1.785e+02  7.210e+04   0.002    0.998
## Superplasticizer47                  3.927e+01  5.187e+04   0.001    0.999
## Superplasticizer48                 -6.097e+01  6.667e+04  -0.001    0.999
## Superplasticizer49                  1.033e+03  2.911e+05   0.004    0.997
## Superplasticizer50                  4.766e+02  2.911e+05   0.002    0.999
## Superplasticizer51                  3.616e+01  1.246e+05   0.000    1.000
## Superplasticizer52                 -1.431e+03  1.381e+06  -0.001    0.999
## Superplasticizer53                 -2.174e+01  7.064e+04   0.000    1.000
## Superplasticizer54                  4.541e+01  2.911e+05   0.000    1.000
## Superplasticizer55                  6.062e+02  2.297e+05   0.003    0.998
## Superplasticizer56                  9.397e+00  7.963e+04   0.000    1.000
## Superplasticizer57                 -8.681e+01  2.710e+04  -0.003    0.997
## Superplasticizer58                  2.289e+03  2.911e+05   0.008    0.994
## Superplasticizer59                  4.766e+02  2.911e+05   0.002    0.999
## Superplasticizer60                 -1.701e+04  2.941e+05  -0.058    0.954
## Superplasticizer61                  3.891e+01  4.232e+04   0.001    0.999
## Superplasticizer62                 -8.236e+03  2.921e+05  -0.028    0.978
## Superplasticizer63                 -3.265e+02  2.911e+05  -0.001    0.999
## Superplasticizer64                 -1.497e+02  2.631e+04  -0.006    0.995
## Superplasticizer65                 -1.012e+02  2.034e+04  -0.005    0.996
## Superplasticizer66                 -7.912e+01  8.731e+03  -0.009    0.993
## Superplasticizer67                  5.460e+02  9.935e+04   0.005    0.996
## Superplasticizer68                  3.582e+02  1.474e+05   0.002    0.998
## Superplasticizer69                  4.766e+02  2.911e+05   0.002    0.999
## Superplasticizer70                  6.489e+03  2.911e+05   0.022    0.982
## Superplasticizer71                  6.389e+02  2.911e+05   0.002    0.998
## Superplasticizer72                 -2.234e+03  2.911e+05  -0.008    0.994
## Superplasticizer73                  1.566e+01  2.680e+04   0.001    1.000
## Superplasticizer74                 -8.379e+01  8.582e+03  -0.010    0.992
## Superplasticizer75                 -7.251e+02  2.911e+05  -0.002    0.998
## Superplasticizer76                  1.674e+02  2.911e+05   0.001    1.000
## Superplasticizer77                  1.431e+01  5.464e+04   0.000    1.000
## Superplasticizer78                  3.432e+02  4.578e+04   0.007    0.994
## Superplasticizer79                  5.036e+01  2.911e+05   0.000    1.000
## Superplasticizer80                  1.294e+01  4.890e+04   0.000    1.000
## Superplasticizer81                 -6.015e+01  8.335e+03  -0.007    0.994
## Superplasticizer82                 -6.886e+01  1.185e+04  -0.006    0.995
## Superplasticizer83                  3.326e+01  2.413e+04   0.001    0.999
## Superplasticizer84                 -1.908e+03  1.455e+06  -0.001    0.999
## Superplasticizer85                 -8.790e+01  7.776e+03  -0.011    0.991
## Superplasticizer86                  9.261e+02  7.116e+04   0.013    0.990
## Superplasticizer87                  4.766e+02  2.928e+05   0.002    0.999
## Superplasticizer88                 -2.456e+01  1.375e+04  -0.002    0.999
## Superplasticizer89                  5.534e+01  4.698e+04   0.001    0.999
## Superplasticizer90                  5.751e+01  2.454e+04   0.002    0.998
## Superplasticizer91                 -8.442e+02  2.914e+05  -0.003    0.998
## Superplasticizer92                  4.766e+02  1.129e+05   0.004    0.997
## Superplasticizer93                 -1.260e+02  1.971e+04  -0.006    0.995
## Superplasticizer94                  4.456e+01  4.646e+04   0.001    0.999
## Superplasticizer95                  1.970e+01  4.042e+04   0.000    1.000
## Superplasticizer96                  1.012e+02  2.554e+05   0.000    1.000
## Superplasticizer97                  4.670e+01  3.098e+04   0.002    0.999
## Superplasticizer98                  1.523e+01  3.957e+04   0.000    1.000
## Superplasticizer99                  2.693e+03  7.918e+05   0.003    0.997
## Superplasticizer100                 1.699e+03  4.012e+05   0.004    0.997
## Superplasticizer101                -4.604e+01  1.191e+04  -0.004    0.997
## Superplasticizer102                 1.059e+01  3.515e+04   0.000    1.000
## Superplasticizer103                -6.174e+01  1.544e+04  -0.004    0.997
## Superplasticizer104                -6.220e+01  1.543e+04  -0.004    0.997
## Superplasticizer105                -9.886e+01  1.149e+04  -0.009    0.993
## Superplasticizer106                -1.198e+02  2.277e+04  -0.005    0.996
## Superplasticizer107                 3.420e+01  2.372e+04   0.001    0.999
## Superplasticizer108                -5.398e+01  9.627e+03  -0.006    0.996
## Superplasticizer109                 8.689e+01  2.029e+04   0.004    0.997
## Superplasticizer110                -4.120e+01  1.558e+04  -0.003    0.998
## Water                               2.278e+00  2.149e+03   0.001    0.999
## strength                            3.879e+00  9.045e+03   0.000    1.000
## Superplasticizer1:Water            -3.621e+00  2.149e+03  -0.002    0.999
## Superplasticizer2:Water                    NA         NA      NA       NA
## Superplasticizer3:Water                    NA         NA      NA       NA
## Superplasticizer4:Water                    NA         NA      NA       NA
## Superplasticizer5:Water                    NA         NA      NA       NA
## Superplasticizer6:Water                    NA         NA      NA       NA
## Superplasticizer7:Water            -2.278e+00  2.149e+03  -0.001    0.999
## Superplasticizer8:Water                    NA         NA      NA       NA
## Superplasticizer9:Water            -2.278e+00  6.205e+01  -0.037    0.971
## Superplasticizer10:Water                   NA         NA      NA       NA
## Superplasticizer11:Water           -1.351e+00  2.149e+03  -0.001    0.999
## Superplasticizer12:Water                   NA         NA      NA       NA
## Superplasticizer13:Water                   NA         NA      NA       NA
## Superplasticizer14:Water           -2.243e+00  2.149e+03  -0.001    0.999
## Superplasticizer15:Water           -1.434e+01  2.149e+03  -0.007    0.995
## Superplasticizer16:Water           -2.278e+00  2.202e+04   0.000    1.000
## Superplasticizer17:Water            4.905e+00  2.226e+03   0.002    0.998
## Superplasticizer18:Water                   NA         NA      NA       NA
## Superplasticizer19:Water           -4.748e-01  2.149e+03   0.000    1.000
## Superplasticizer20:Water           -2.199e+00  2.149e+03  -0.001    0.999
## Superplasticizer21:Water            6.501e+00  2.149e+03   0.003    0.998
## Superplasticizer22:Water           -2.278e+00  1.176e+03  -0.002    0.998
## Superplasticizer23:Water           -2.278e+00  2.149e+03  -0.001    0.999
## Superplasticizer24:Water           -1.069e+01  2.150e+03  -0.005    0.996
## Superplasticizer25:Water                   NA         NA      NA       NA
## Superplasticizer26:Water                   NA         NA      NA       NA
## Superplasticizer27:Water            3.813e+00  3.643e+02   0.010    0.992
## Superplasticizer28:Water           -2.032e+00  8.211e+00  -0.247    0.805
## Superplasticizer29:Water                   NA         NA      NA       NA
## Superplasticizer30:Water            1.335e+00  2.149e+03   0.001    1.000
## Superplasticizer31:Water           -1.726e+01  1.476e+03  -0.012    0.991
## Superplasticizer32:Water           -1.795e+00  2.149e+03  -0.001    0.999
## Superplasticizer33:Water                   NA         NA      NA       NA
## Superplasticizer34:Water                   NA         NA      NA       NA
## Superplasticizer35:Water                   NA         NA      NA       NA
## Superplasticizer36:Water            4.584e+00  2.149e+03   0.002    0.998
## Superplasticizer37:Water            1.117e+01  1.269e+03   0.009    0.993
## Superplasticizer38:Water           -4.377e-01  2.149e+03   0.000    1.000
## Superplasticizer39:Water           -6.568e-02  1.372e+03   0.000    1.000
## Superplasticizer40:Water           -2.278e+00  2.149e+03  -0.001    0.999
## Superplasticizer41:Water           -4.548e+00  1.463e+03  -0.003    0.998
## Superplasticizer42:Water            2.044e+00  4.899e+02   0.004    0.997
## Superplasticizer43:Water           -1.306e+00  3.414e+02  -0.004    0.997
## Superplasticizer44:Water                   NA         NA      NA       NA
## Superplasticizer45:Water            2.863e+00  2.149e+03   0.001    0.999
## Superplasticizer46:Water           -1.101e+00  8.240e+01  -0.013    0.989
## Superplasticizer47:Water                   NA         NA      NA       NA
## Superplasticizer48:Water                   NA         NA      NA       NA
## Superplasticizer49:Water           -5.794e+00  2.149e+03  -0.003    0.998
## Superplasticizer50:Water           -2.278e+00  2.149e+03  -0.001    0.999
## Superplasticizer51:Water                   NA         NA      NA       NA
## Superplasticizer52:Water            6.986e+00  7.278e+03   0.001    0.999
## Superplasticizer53:Water                   NA         NA      NA       NA
## Superplasticizer54:Water           -2.780e-01  2.149e+03   0.000    1.000
## Superplasticizer55:Water           -3.559e+00  1.197e+03  -0.003    0.998
## Superplasticizer56:Water                   NA         NA      NA       NA
## Superplasticizer57:Water                   NA         NA      NA       NA
## Superplasticizer58:Water           -1.381e+01  2.149e+03  -0.006    0.995
## Superplasticizer59:Water           -2.278e+00  2.149e+03  -0.001    0.999
## Superplasticizer60:Water            9.987e+01  2.163e+03   0.046    0.963
## Superplasticizer61:Water                   NA         NA      NA       NA
## Superplasticizer62:Water            4.481e+01  2.153e+03   0.021    0.983
## Superplasticizer63:Water            2.595e+00  2.149e+03   0.001    0.999
## Superplasticizer64:Water                   NA         NA      NA       NA
## Superplasticizer65:Water                   NA         NA      NA       NA
## Superplasticizer66:Water                   NA         NA      NA       NA
## Superplasticizer67:Water           -3.074e+00  3.151e+02  -0.010    0.992
## Superplasticizer68:Water           -1.878e+00  6.965e+02  -0.003    0.998
## Superplasticizer69:Water           -2.278e+00  2.149e+03  -0.001    0.999
## Superplasticizer70:Water           -3.527e+01  2.149e+03  -0.016    0.987
## Superplasticizer71:Water           -3.862e+00  2.149e+03  -0.002    0.999
## Superplasticizer72:Water            1.432e+01  2.149e+03   0.007    0.995
## Superplasticizer73:Water                   NA         NA      NA       NA
## Superplasticizer74:Water                   NA         NA      NA       NA
## Superplasticizer75:Water            4.668e+00  2.149e+03   0.002    0.998
## Superplasticizer76:Water           -7.625e-01  2.149e+03   0.000    1.000
## Superplasticizer77:Water                   NA         NA      NA       NA
## Superplasticizer78:Water           -1.946e+00  2.386e+02  -0.008    0.993
## Superplasticizer79:Water            1.494e-01  2.149e+03   0.000    1.000
## Superplasticizer80:Water                   NA         NA      NA       NA
## Superplasticizer81:Water                   NA         NA      NA       NA
## Superplasticizer82:Water                   NA         NA      NA       NA
## Superplasticizer83:Water                   NA         NA      NA       NA
## Superplasticizer84:Water            1.056e+01  8.363e+03   0.001    0.999
## Superplasticizer85:Water                   NA         NA      NA       NA
## Superplasticizer86:Water           -5.624e+00  1.395e+02  -0.040    0.968
## Superplasticizer87:Water           -2.278e+00  2.156e+03  -0.001    0.999
## Superplasticizer88:Water                   NA         NA      NA       NA
## Superplasticizer89:Water                   NA         NA      NA       NA
## Superplasticizer90:Water                   NA         NA      NA       NA
## Superplasticizer91:Water            5.718e+00  2.151e+03   0.003    0.998
## Superplasticizer92:Water           -2.278e+00  1.119e+03  -0.002    0.998
## Superplasticizer93:Water                   NA         NA      NA       NA
## Superplasticizer94:Water                   NA         NA      NA       NA
## Superplasticizer95:Water                   NA         NA      NA       NA
## Superplasticizer96:Water           -3.435e-01  1.806e+03   0.000    1.000
## Superplasticizer97:Water                   NA         NA      NA       NA
## Superplasticizer98:Water                   NA         NA      NA       NA
## Superplasticizer99:Water           -1.665e+01  4.789e+03  -0.003    0.997
## Superplasticizer100:Water          -1.040e+01  2.332e+03  -0.004    0.996
## Superplasticizer101:Water                  NA         NA      NA       NA
## Superplasticizer102:Water                  NA         NA      NA       NA
## Superplasticizer103:Water                  NA         NA      NA       NA
## Superplasticizer104:Water                  NA         NA      NA       NA
## Superplasticizer105:Water                  NA         NA      NA       NA
## Superplasticizer106:Water                  NA         NA      NA       NA
## Superplasticizer107:Water                  NA         NA      NA       NA
## Superplasticizer108:Water                  NA         NA      NA       NA
## Superplasticizer109:Water                  NA         NA      NA       NA
## Superplasticizer110:Water                  NA         NA      NA       NA
## Superplasticizer1:strength         -1.568e+01  9.045e+03  -0.002    0.999
## Superplasticizer2:strength         -4.400e-01  4.095e+03   0.000    1.000
## Superplasticizer3:strength         -2.660e+01  5.503e+04   0.000    1.000
## Superplasticizer4:strength                 NA         NA      NA       NA
## Superplasticizer5:strength                 NA         NA      NA       NA
## Superplasticizer6:strength         -3.879e+00  1.288e+03  -0.003    0.998
## Superplasticizer7:strength         -3.879e+00  9.045e+03   0.000    1.000
## Superplasticizer8:strength                 NA         NA      NA       NA
## Superplasticizer9:strength         -3.879e+00  2.558e+03  -0.002    0.999
## Superplasticizer10:strength        -1.043e+00  2.430e+03   0.000    1.000
## Superplasticizer11:strength        -5.529e-01  9.045e+03   0.000    1.000
## Superplasticizer12:strength                NA         NA      NA       NA
## Superplasticizer13:strength         1.072e+00  9.568e+02   0.001    0.999
## Superplasticizer14:strength         4.628e+00  9.045e+03   0.001    1.000
## Superplasticizer15:strength        -1.166e+02  9.045e+03  -0.013    0.990
## Superplasticizer16:strength        -3.874e+00  1.248e+05   0.000    1.000
## Superplasticizer17:strength                NA         NA      NA       NA
## Superplasticizer18:strength        -1.319e+00  3.189e+03   0.000    1.000
## Superplasticizer19:strength         5.365e+00  9.045e+03   0.001    1.000
## Superplasticizer20:strength         1.119e+00  9.045e+03   0.000    1.000
## Superplasticizer21:strength         4.986e+01  9.046e+03   0.006    0.996
## Superplasticizer22:strength        -3.879e+00  1.052e+03  -0.004    0.997
## Superplasticizer23:strength        -3.879e+00  9.045e+03   0.000    1.000
## Superplasticizer24:strength        -7.597e+01  9.048e+03  -0.008    0.993
## Superplasticizer25:strength                NA         NA      NA       NA
## Superplasticizer26:strength                NA         NA      NA       NA
## Superplasticizer27:strength        -8.968e-01  2.979e+03   0.000    1.000
## Superplasticizer28:strength        -1.307e+00  1.467e+03  -0.001    0.999
## Superplasticizer29:strength                NA         NA      NA       NA
## Superplasticizer30:strength         2.205e+01  9.045e+03   0.002    0.998
## Superplasticizer31:strength        -1.698e+00  2.545e+03  -0.001    0.999
## Superplasticizer32:strength        -4.637e-01  9.045e+03   0.000    1.000
## Superplasticizer33:strength                NA         NA      NA       NA
## Superplasticizer34:strength                NA         NA      NA       NA
## Superplasticizer35:strength                NA         NA      NA       NA
## Superplasticizer36:strength         5.019e+01  9.045e+03   0.006    0.996
## Superplasticizer37:strength        -7.915e-01  1.773e+03   0.000    1.000
## Superplasticizer38:strength         9.708e+00  9.045e+03   0.001    0.999
## Superplasticizer39:strength        -1.819e+00  1.416e+03  -0.001    0.999
## Superplasticizer40:strength        -3.879e+00  9.045e+03   0.000    1.000
## Superplasticizer41:strength        -1.709e+00  2.124e+03  -0.001    0.999
## Superplasticizer42:strength        -1.749e+00  1.811e+03  -0.001    0.999
## Superplasticizer43:strength                NA         NA      NA       NA
## Superplasticizer44:strength                NA         NA      NA       NA
## Superplasticizer45:strength         1.454e+01  9.045e+03   0.002    0.999
## Superplasticizer46:strength        -1.968e+00  2.150e+03  -0.001    0.999
## Superplasticizer47:strength        -1.121e+00  1.116e+03  -0.001    0.999
## Superplasticizer48:strength                NA         NA      NA       NA
## Superplasticizer49:strength        -1.227e+01  9.045e+03  -0.001    0.999
## Superplasticizer50:strength        -3.879e+00  9.045e+03   0.000    1.000
## Superplasticizer51:strength        -3.879e+00  3.285e+03  -0.001    0.999
## Superplasticizer52:strength                NA         NA      NA       NA
## Superplasticizer53:strength        -4.499e-01  1.678e+03   0.000    1.000
## Superplasticizer54:strength        -5.381e+00  9.045e+03  -0.001    1.000
## Superplasticizer55:strength        -2.014e+00  8.802e+02  -0.002    0.998
## Superplasticizer56:strength        -1.508e+00  1.945e+03  -0.001    0.999
## Superplasticizer57:strength                NA         NA      NA       NA
## Superplasticizer58:strength        -8.089e+01  9.045e+03  -0.009    0.993
## Superplasticizer59:strength        -3.879e+00  9.045e+03   0.000    1.000
## Superplasticizer60:strength         1.036e+03  9.394e+03   0.110    0.912
## Superplasticizer61:strength        -1.297e+00  8.292e+02  -0.002    0.999
## Superplasticizer62:strength         1.605e+02  9.056e+03   0.018    0.986
## Superplasticizer63:strength         2.223e+01  9.045e+03   0.002    0.998
## Superplasticizer64:strength                NA         NA      NA       NA
## Superplasticizer65:strength                NA         NA      NA       NA
## Superplasticizer66:strength                NA         NA      NA       NA
## Superplasticizer67:strength        -1.576e+00  1.052e+03  -0.001    0.999
## Superplasticizer68:strength        -2.784e+00  7.782e+02  -0.004    0.997
## Superplasticizer69:strength        -3.879e+00  9.045e+03   0.000    1.000
## Superplasticizer70:strength        -2.077e+02  9.047e+03  -0.023    0.982
## Superplasticizer71:strength        -7.429e+00  9.045e+03  -0.001    0.999
## Superplasticizer72:strength         7.655e+01  9.045e+03   0.008    0.993
## Superplasticizer73:strength        -1.736e+00  3.572e+02  -0.005    0.996
## Superplasticizer74:strength                NA         NA      NA       NA
## Superplasticizer75:strength         2.303e+01  9.045e+03   0.003    0.998
## Superplasticizer76:strength        -5.666e-01  9.045e+03   0.000    1.000
## Superplasticizer77:strength        -1.411e+00  1.199e+03  -0.001    0.999
## Superplasticizer78:strength        -1.857e+00  6.389e+01  -0.029    0.977
## Superplasticizer79:strength         6.293e+00  9.045e+03   0.001    0.999
## Superplasticizer80:strength        -1.387e+00  1.027e+03  -0.001    0.999
## Superplasticizer81:strength                NA         NA      NA       NA
## Superplasticizer82:strength                NA         NA      NA       NA
## Superplasticizer83:strength        -4.302e-01  2.743e+02  -0.002    0.999
## Superplasticizer84:strength                NA         NA      NA       NA
## Superplasticizer85:strength                NA         NA      NA       NA
## Superplasticizer86:strength        -1.153e+00  1.040e+03  -0.001    0.999
## Superplasticizer87:strength        -3.879e+00  9.088e+03   0.000    1.000
## Superplasticizer88:strength                NA         NA      NA       NA
## Superplasticizer89:strength        -2.457e+00  9.695e+02  -0.003    0.998
## Superplasticizer90:strength        -1.763e+00  2.871e+02  -0.006    0.995
## Superplasticizer91:strength         2.673e+01  9.049e+03   0.003    0.998
## Superplasticizer92:strength        -3.879e+00  2.150e+03  -0.002    0.999
## Superplasticizer93:strength                NA         NA      NA       NA
## Superplasticizer94:strength                NA         NA      NA       NA
## Superplasticizer95:strength        -1.471e+00  7.718e+02  -0.002    0.998
## Superplasticizer96:strength                NA         NA      NA       NA
## Superplasticizer97:strength                NA         NA      NA       NA
## Superplasticizer98:strength        -1.664e+00  7.463e+02  -0.002    0.998
## Superplasticizer99:strength                NA         NA      NA       NA
## Superplasticizer100:strength               NA         NA      NA       NA
## Superplasticizer101:strength               NA         NA      NA       NA
## Superplasticizer102:strength       -1.527e+00  6.123e+02  -0.002    0.998
## Superplasticizer103:strength               NA         NA      NA       NA
## Superplasticizer104:strength               NA         NA      NA       NA
## Superplasticizer105:strength               NA         NA      NA       NA
## Superplasticizer106:strength               NA         NA      NA       NA
## Superplasticizer107:strength       -2.109e+00  2.615e+02  -0.008    0.994
## Superplasticizer108:strength               NA         NA      NA       NA
## Superplasticizer109:strength       -1.709e+00  9.695e+02  -0.002    0.999
## Superplasticizer110:strength               NA         NA      NA       NA
## Water:strength                     -4.003e-07  6.378e+01   0.000    1.000
## Superplasticizer1:Water:strength    7.783e-02  6.378e+01   0.001    0.999
## Superplasticizer2:Water:strength           NA         NA      NA       NA
## Superplasticizer3:Water:strength           NA         NA      NA       NA
## Superplasticizer4:Water:strength           NA         NA      NA       NA
## Superplasticizer5:Water:strength           NA         NA      NA       NA
## Superplasticizer6:Water:strength           NA         NA      NA       NA
## Superplasticizer7:Water:strength    4.004e-07  6.379e+01   0.000    1.000
## Superplasticizer8:Water:strength           NA         NA      NA       NA
## Superplasticizer9:Water:strength           NA         NA      NA       NA
## Superplasticizer10:Water:strength          NA         NA      NA       NA
## Superplasticizer11:Water:strength  -9.430e-03  6.379e+01   0.000    1.000
## Superplasticizer12:Water:strength          NA         NA      NA       NA
## Superplasticizer13:Water:strength          NA         NA      NA       NA
## Superplasticizer14:Water:strength  -2.662e-02  6.379e+01   0.000    1.000
## Superplasticizer15:Water:strength   5.923e-01  6.379e+01   0.009    0.993
## Superplasticizer16:Water:strength  -2.281e-05  6.586e+02   0.000    1.000
## Superplasticizer17:Water:strength          NA         NA      NA       NA
## Superplasticizer18:Water:strength          NA         NA      NA       NA
## Superplasticizer19:Water:strength  -4.115e-02  6.379e+01  -0.001    0.999
## Superplasticizer20:Water:strength  -1.432e-02  6.378e+01   0.000    1.000
## Superplasticizer21:Water:strength  -2.653e-01  6.379e+01  -0.004    0.997
## Superplasticizer22:Water:strength          NA         NA      NA       NA
## Superplasticizer23:Water:strength   4.003e-07  6.378e+01   0.000    1.000
## Superplasticizer24:Water:strength   3.881e-01  6.380e+01   0.006    0.995
## Superplasticizer25:Water:strength          NA         NA      NA       NA
## Superplasticizer26:Water:strength          NA         NA      NA       NA
## Superplasticizer27:Water:strength          NA         NA      NA       NA
## Superplasticizer28:Water:strength          NA         NA      NA       NA
## Superplasticizer29:Water:strength          NA         NA      NA       NA
## Superplasticizer30:Water:strength  -1.322e-01  6.379e+01  -0.002    0.998
## Superplasticizer31:Water:strength          NA         NA      NA       NA
## Superplasticizer32:Water:strength  -1.492e-02  6.378e+01   0.000    1.000
## Superplasticizer33:Water:strength          NA         NA      NA       NA
## Superplasticizer34:Water:strength          NA         NA      NA       NA
## Superplasticizer35:Water:strength          NA         NA      NA       NA
## Superplasticizer36:Water:strength  -3.047e-01  6.379e+01  -0.005    0.996
## Superplasticizer37:Water:strength          NA         NA      NA       NA
## Superplasticizer38:Water:strength  -6.728e-02  6.378e+01  -0.001    0.999
## Superplasticizer39:Water:strength          NA         NA      NA       NA
## Superplasticizer40:Water:strength   4.003e-07  6.378e+01   0.000    1.000
## Superplasticizer41:Water:strength          NA         NA      NA       NA
## Superplasticizer42:Water:strength          NA         NA      NA       NA
## Superplasticizer43:Water:strength          NA         NA      NA       NA
## Superplasticizer44:Water:strength          NA         NA      NA       NA
## Superplasticizer45:Water:strength  -9.600e-02  6.379e+01  -0.002    0.999
## Superplasticizer46:Water:strength          NA         NA      NA       NA
## Superplasticizer47:Water:strength          NA         NA      NA       NA
## Superplasticizer48:Water:strength          NA         NA      NA       NA
## Superplasticizer49:Water:strength   5.478e-02  6.378e+01   0.001    0.999
## Superplasticizer50:Water:strength   4.003e-07  6.378e+01   0.000    1.000
## Superplasticizer51:Water:strength          NA         NA      NA       NA
## Superplasticizer52:Water:strength          NA         NA      NA       NA
## Superplasticizer53:Water:strength          NA         NA      NA       NA
## Superplasticizer54:Water:strength   2.006e-02  6.379e+01   0.000    1.000
## Superplasticizer55:Water:strength          NA         NA      NA       NA
## Superplasticizer56:Water:strength          NA         NA      NA       NA
## Superplasticizer57:Water:strength          NA         NA      NA       NA
## Superplasticizer58:Water:strength   4.896e-01  6.379e+01   0.008    0.994
## Superplasticizer59:Water:strength   4.003e-07  6.378e+01   0.000    1.000
## Superplasticizer60:Water:strength  -6.098e+00  6.550e+01  -0.093    0.926
## Superplasticizer61:Water:strength          NA         NA      NA       NA
## Superplasticizer62:Water:strength  -8.897e-01  6.383e+01  -0.014    0.989
## Superplasticizer63:Water:strength  -1.574e-01  6.379e+01  -0.002    0.998
## Superplasticizer64:Water:strength          NA         NA      NA       NA
## Superplasticizer65:Water:strength          NA         NA      NA       NA
## Superplasticizer66:Water:strength          NA         NA      NA       NA
## Superplasticizer67:Water:strength          NA         NA      NA       NA
## Superplasticizer68:Water:strength          NA         NA      NA       NA
## Superplasticizer69:Water:strength   4.003e-07  6.378e+01   0.000    1.000
## Superplasticizer70:Water:strength   1.108e+00  6.380e+01   0.017    0.986
## Superplasticizer71:Water:strength   3.390e-02  6.378e+01   0.001    1.000
## Superplasticizer72:Water:strength  -4.893e-01  6.379e+01  -0.008    0.994
## Superplasticizer73:Water:strength          NA         NA      NA       NA
## Superplasticizer74:Water:strength          NA         NA      NA       NA
## Superplasticizer75:Water:strength  -1.565e-01  6.379e+01  -0.002    0.998
## Superplasticizer76:Water:strength  -7.863e-03  6.379e+01   0.000    1.000
## Superplasticizer77:Water:strength          NA         NA      NA       NA
## Superplasticizer78:Water:strength          NA         NA      NA       NA
## Superplasticizer79:Water:strength  -5.793e-02  6.378e+01  -0.001    0.999
## Superplasticizer80:Water:strength          NA         NA      NA       NA
## Superplasticizer81:Water:strength          NA         NA      NA       NA
## Superplasticizer82:Water:strength          NA         NA      NA       NA
## Superplasticizer83:Water:strength          NA         NA      NA       NA
## Superplasticizer84:Water:strength          NA         NA      NA       NA
## Superplasticizer85:Water:strength          NA         NA      NA       NA
## Superplasticizer86:Water:strength          NA         NA      NA       NA
## Superplasticizer87:Water:strength   4.003e-07  6.397e+01   0.000    1.000
## Superplasticizer88:Water:strength          NA         NA      NA       NA
## Superplasticizer89:Water:strength          NA         NA      NA       NA
## Superplasticizer90:Water:strength          NA         NA      NA       NA
## Superplasticizer91:Water:strength  -1.856e-01  6.381e+01  -0.003    0.998
## Superplasticizer92:Water:strength          NA         NA      NA       NA
## Superplasticizer93:Water:strength          NA         NA      NA       NA
## Superplasticizer94:Water:strength          NA         NA      NA       NA
## Superplasticizer95:Water:strength          NA         NA      NA       NA
## Superplasticizer96:Water:strength          NA         NA      NA       NA
## Superplasticizer97:Water:strength          NA         NA      NA       NA
## Superplasticizer98:Water:strength          NA         NA      NA       NA
## Superplasticizer99:Water:strength          NA         NA      NA       NA
## Superplasticizer100:Water:strength         NA         NA      NA       NA
## Superplasticizer101:Water:strength         NA         NA      NA       NA
## Superplasticizer102:Water:strength         NA         NA      NA       NA
## Superplasticizer103:Water:strength         NA         NA      NA       NA
## Superplasticizer104:Water:strength         NA         NA      NA       NA
## Superplasticizer105:Water:strength         NA         NA      NA       NA
## Superplasticizer106:Water:strength         NA         NA      NA       NA
## Superplasticizer107:Water:strength         NA         NA      NA       NA
## Superplasticizer108:Water:strength         NA         NA      NA       NA
## Superplasticizer109:Water:strength         NA         NA      NA       NA
## Superplasticizer110:Water:strength         NA         NA      NA       NA
## 
## Residual standard error: 52.56 on 753 degrees of freedom
## Multiple R-squared:  0.4934, Adjusted R-squared:  0.3077 
## F-statistic: 2.657 on 276 and 753 DF,  p-value: < 2.2e-16

The Shapiro-Wilk normality test returns a p-value which is very small (less than 0.1) which shows that the data is normally distributed.The Normal Q-Q plot conforms normality for the residuals.

The scatter plot however indicates some trend i.e. there is a uniform decrease in the residual values over the entire dynamic range.This is opposite to our earlier results so the data might not be considered a very good fit. There are essentially 2 possibilities: 1.The slope of the regression line was computed incorrectly since the data shows trend. 2.The intercept of the regression line might or might not have been computed correctly.

The final analysis of fitting a model with different slopes for each factor level is again done to check the appropriateness of our initial analysis. We see from the results that none of the Superplasticizer:strength values give statistically significant results (all of them have p value greater than 0.05), which means our analysis was appropriate.Same is the case with Superplasticizer:Water probability values (not significant) indicating validity of our result.

References

Wikipedia

Data Source: https://archive.ics.uci.edu/ml/machine-learning-databases/concrete/compressive/