library(reshape2) #  melt
## Warning: package 'reshape2' was built under R version 3.4.3
library(MASS) #  lda
library(psy) #  cronbach
library(psych) # KMO
## 
## Attaching package: 'psych'
## The following object is masked from 'package:psy':
## 
##     wkappa
library(Hmisc) # correlation matrix
## Warning: package 'Hmisc' was built under R version 3.4.3
## Loading required package: lattice
## Loading required package: survival
## Loading required package: Formula
## Loading required package: ggplot2
## Warning: package 'ggplot2' was built under R version 3.4.3
## 
## Attaching package: 'ggplot2'
## The following objects are masked from 'package:psych':
## 
##     %+%, alpha
## 
## Attaching package: 'Hmisc'
## The following object is masked from 'package:psych':
## 
##     describe
## The following objects are masked from 'package:base':
## 
##     format.pval, units
library(psych) #KMO
library(Hmisc) # correlation matrix
library(mapproj)  #  map
## Warning: package 'mapproj' was built under R version 3.4.2
## Loading required package: maps
## Warning: package 'maps' was built under R version 3.4.2
cat("\014")  # cleans screen

rm(list=ls(all=TRUE))  # remove variables in working memory
setwd("C:/Users/Erik Ernesto Vazquez/Downloads")  # sets working directory
MainStudy<-read.csv("MainStudyNov2.csv", header=T)
## MainStudy<-read.csv("MonaMourMainStudyUS.csv", header=T)  # reads raw data from Qualtrics
## MainStudy<-read.csv("MonaMourMainStudyMX.csv", header=T)  # reads raw data from Qualtrics

MainStudy1<-subset(MainStudy,MainStudy$Q40_Page.Submit!=""&MainStudy$FL_17_DO!="")
MainStudy1<-subset(MainStudy1,MainStudy1$Q4==3|MainStudy1$Q4==4) ## Only Desktop and Laptop PC

## recoding mobile and tablet (reverse)
MainStudy2<-subset(MainStudy,MainStudy$Q40_Page.Submit!=""&MainStudy$FL_17_DO!="")
MainStudy2<-subset(MainStudy2,MainStudy2$Q4==1|MainStudy2$Q4==2) ## Only Mobile and Tablet

MainStudy2$Q19_1<-10-MainStudy2$Q19_1
MainStudy2$Q19_2<-10-MainStudy2$Q19_2
MainStudy2$Q19_3<-10-MainStudy2$Q19_3
MainStudy2$Q19_4<-10-MainStudy2$Q19_4

MainStudy2$Q21_7<-10-MainStudy2$Q21_7
MainStudy2$Q21_8<-10-MainStudy2$Q21_8
MainStudy2$Q21_9<-10-MainStudy2$Q21_9

MainStudy<-rbind(MainStudy1,MainStudy2)

## Filtering out low income participants
summary(MainStudy$Q22)
##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##   1.000   2.000   4.000   3.895   5.000   9.000
table(MainStudy$Q22)
## 
##   1   2   3   4   5   6   7   8   9 
##  77  87  63  95 114  55  36  11   7
MainStudy<-subset(MainStudy,MainStudy$Q22>4)
table(MainStudy$Q25)
## 
##   1   2   3   4   5   6 
## 159  18  11   1  31   3
MainStudy<-subset(MainStudy,MainStudy$Q25==1)

table(MainStudy$Q4)
## 
##  1  2  3  4 
## 14 11 87 47
table(MainStudy$FL_17_DO)
## 
##        Block1 Block2 Block3 Block4 Block5 Block6 
##      0     33     32     23     22     26     23
## Age of the sample
mean(MainStudy$Q26)
## [1] 39.03145
sd(MainStudy$Q26)
## [1] 11.45847
MainStudy1<-subset(MainStudy,MainStudy$FL_17_DO=="Block1")
MainStudy2<-subset(MainStudy,MainStudy$FL_17_DO=="Block2")
MainStudy3<-subset(MainStudy,MainStudy$FL_17_DO=="Block3")
MainStudy4<-subset(MainStudy,MainStudy$FL_17_DO=="Block4")
MainStudy5<-subset(MainStudy,MainStudy$FL_17_DO=="Block5")
MainStudy6<-subset(MainStudy,MainStudy$FL_17_DO=="Block6")


## MainStudy<-rbind(MainStudy1[1:74,],MainStudy2[1:74,],MainStudy3[1:74,],
##                MainStudy4[1:74,],MainStudy5[1:74,],MainStudy6[1:74,])

## table(MainStudy$FL_17_DO)

## index<-sample(1:nrow(MainStudy),10000,replace=T)
## MainStudy<-as.data.frame(MainStudy[index,])

table(MainStudy$FL_17_DO)
## 
##        Block1 Block2 Block3 Block4 Block5 Block6 
##      0     33     32     23     22     26     23
cronbach(cbind(MainStudy$Q19_1,MainStudy$Q19_2,MainStudy$Q19_3,MainStudy$Q19_4))
## $sample.size
## [1] 159
## 
## $number.of.items
## [1] 4
## 
## $alpha
## [1] 0.9191072
cronbach(cbind(MainStudy$Q21_7,MainStudy$Q21_8,MainStudy$Q21_9))
## $sample.size
## [1] 159
## 
## $number.of.items
## [1] 3
## 
## $alpha
## [1] 0.9710056
MainStudy$Auth<-(MainStudy$Q19_1+MainStudy$Q19_2+MainStudy$Q19_3+MainStudy$Q19_4)/4
MainStudy$PurchInt<-(MainStudy$Q21_7+MainStudy$Q21_8+MainStudy$Q21_9)/3

MainStudy$UrbanLvl<-ifelse(MainStudy$FL_17_DO=="Block1"|
                             MainStudy$FL_17_DO=="Block2"|
                             MainStudy$FL_17_DO=="Block3",1,2)

MainStudy$MCLvl<-ifelse(MainStudy$FL_17_DO=="Block1"|
                          MainStudy$FL_17_DO=="Block4",1,
                        (ifelse(MainStudy$FL_17_DO=="Block2"|
                                  MainStudy$FL_17_DO=="Block5",2,3)))
table(MainStudy$FL_17_DO)
## 
##        Block1 Block2 Block3 Block4 Block5 Block6 
##      0     33     32     23     22     26     23
table(MainStudy$UrbanLvl)
## 
##  1  2 
## 88 71
table(MainStudy$MCLvl)
## 
##  1  2  3 
## 55 58 46
aggregate(MainStudy$Auth,list(MainStudy$UrbanLvl),mean)
##   Group.1        x
## 1       1 4.795455
## 2       2 4.137324
aggregate(MainStudy$Auth,list(MainStudy$UrbanLvl),sd)
##   Group.1        x
## 1       1 1.848635
## 2       2 1.431027
aggregate(MainStudy$Auth,list(MainStudy$MCLvl),mean)
##   Group.1        x
## 1       1 4.490909
## 2       2 4.599138
## 3       3 4.391304
aggregate(MainStudy$Auth,list(MainStudy$MCLvl),sd)
##   Group.1        x
## 1       1 1.580380
## 2       2 1.743371
## 3       3 1.816324
t.test(MainStudy$Auth~MainStudy$UrbanLvl) ## H1 Approved
## 
##  Welch Two Sample t-test
## 
## data:  MainStudy$Auth by MainStudy$UrbanLvl
## t = 2.5298, df = 156.75, p-value = 0.0124
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  0.1442811 1.1719801
## sample estimates:
## mean in group 1 mean in group 2 
##        4.795455        4.137324
summary(aov(Auth~as.factor(MCLvl),MainStudy)) ## H2 Rejected
##                   Df Sum Sq Mean Sq F value Pr(>F)
## as.factor(MCLvl)   2    1.1  0.5588   0.191  0.826
## Residuals        156  456.6  2.9267
aov.out<-aov(Auth~as.factor(MCLvl),MainStudy)
TukeyHSD(aov.out)
##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = Auth ~ as.factor(MCLvl), data = MainStudy)
## 
## $`as.factor(MCLvl)`
##            diff        lwr       upr     p adj
## 2-1  0.10822884 -0.6536825 0.8701402 0.9396467
## 3-1 -0.09960474 -0.9084417 0.7092322 0.9542851
## 3-2 -0.20783358 -1.0070867 0.5914195 0.8119659
summary(lm(Auth~MCLvl,MainStudy))
## 
## Call:
## lm(formula = Auth ~ MCLvl, data = MainStudy)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -3.5437 -1.2490 -0.0437  1.0010  4.5456 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  4.58832    0.35755  12.833   <2e-16 ***
## MCLvl       -0.04464    0.17029  -0.262    0.794    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.707 on 157 degrees of freedom
## Multiple R-squared:  0.0004375,  Adjusted R-squared:  -0.005929 
## F-statistic: 0.06872 on 1 and 157 DF,  p-value: 0.7936
summary(lm(PurchInt~Auth,MainStudy)) ## H3 Approved
## 
## Call:
## lm(formula = PurchInt ~ Auth, data = MainStudy)
## 
## Residuals:
##    Min     1Q Median     3Q    Max 
## -6.118 -1.673  0.449  1.882  3.582 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)   4.6620     0.5149   9.054  5.1e-16 ***
## Auth          0.3778     0.1070   3.530 0.000546 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 2.29 on 157 degrees of freedom
## Multiple R-squared:  0.07352,    Adjusted R-squared:  0.06762 
## F-statistic: 12.46 on 1 and 157 DF,  p-value: 0.0005462
## Interaction effects
summary(aov(Auth~UrbanLvl*MCLvl,MainStudy)) ## There are not interaction effects
##                 Df Sum Sq Mean Sq F value Pr(>F)  
## UrbanLvl         1   17.0  17.020   5.991 0.0155 *
## MCLvl            1    0.0   0.014   0.005 0.9441  
## UrbanLvl:MCLvl   1    0.3   0.330   0.116 0.7338  
## Residuals      155  440.3   2.841                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
summary(lm(Auth~UrbanLvl*MCLvl,MainStudy)) ## There are not interaction effects
## 
## Call:
## lm(formula = Auth ~ UrbanLvl * MCLvl, data = MainStudy)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -3.8402 -1.2368  0.0363  0.9369  4.8616 
## 
## Coefficients:
##                Estimate Std. Error t value Pr(>|t|)    
## (Intercept)      5.1503     1.0781   4.777 4.09e-06 ***
## UrbanLvl        -0.4307     0.7160  -0.601    0.548    
## MCLvl            0.1557     0.5199   0.299    0.765    
## UrbanLvl:MCLvl  -0.1155     0.3390  -0.341    0.734    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.685 on 155 degrees of freedom
## Multiple R-squared:  0.03794,    Adjusted R-squared:  0.01932 
## F-statistic: 2.037 on 3 and 155 DF,  p-value: 0.1109
## Verifying equivalency of groups
t.test(as.numeric(MainStudy$Q26)~MainStudy$UrbanLvl) ## Age
## 
##  Welch Two Sample t-test
## 
## data:  as.numeric(MainStudy$Q26) by MainStudy$UrbanLvl
## t = 1.7092, df = 153.34, p-value = 0.08944
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -0.4808336  6.6511281
## sample estimates:
## mean in group 1 mean in group 2 
##        40.40909        37.32394
summary(aov(as.numeric(Q26)~as.factor(MCLvl),MainStudy)) ## Age
##                   Df Sum Sq Mean Sq F value Pr(>F)
## as.factor(MCLvl)   2    147    73.3   0.555  0.575
## Residuals        156  20598   132.0
t.test(as.numeric(MainStudy$Q22)~MainStudy$UrbanLvl) ## Income
## 
##  Welch Two Sample t-test
## 
## data:  as.numeric(MainStudy$Q22) by MainStudy$UrbanLvl
## t = 0.82741, df = 154.1, p-value = 0.4093
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -0.1776621  0.4337441
## sample estimates:
## mean in group 1 mean in group 2 
##        5.818182        5.690141
summary(aov(as.numeric(Q22)~as.factor(MCLvl),MainStudy)) ## Income
##                   Df Sum Sq Mean Sq F value Pr(>F)  
## as.factor(MCLvl)   2   6.14  3.0690   3.307 0.0392 *
## Residuals        156 144.78  0.9281                 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
t.test(as.numeric(MainStudy$Q23)~MainStudy$UrbanLvl) ## Education *** unbalanced
## 
##  Welch Two Sample t-test
## 
## data:  as.numeric(MainStudy$Q23) by MainStudy$UrbanLvl
## t = 1.0177, df = 150.5, p-value = 0.3104
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -0.2746821  0.8582288
## sample estimates:
## mean in group 1 mean in group 2 
##        11.19318        10.90141
summary(aov(as.numeric(Q23)~as.factor(MCLvl),MainStudy)) ## Education
##                   Df Sum Sq Mean Sq F value Pr(>F)
## as.factor(MCLvl)   2   14.1   7.068   2.217  0.112
## Residuals        156  497.2   3.187
summary(lm(Auth~Q23,MainStudy)) ## Does not affect Auth
## 
## Call:
## lm(formula = Auth ~ Q23, data = MainStudy)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -3.8387 -1.2186 -0.1646  0.8844  4.6834 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)   
## (Intercept)  2.57651    0.83175   3.098  0.00231 **
## Q23          0.17401    0.07422   2.345  0.02029 * 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.678 on 157 degrees of freedom
## Multiple R-squared:  0.03383,    Adjusted R-squared:  0.02768 
## F-statistic: 5.498 on 1 and 157 DF,  p-value: 0.02029
t.test(as.numeric(MainStudy$Q24)~MainStudy$UrbanLvl) ## Purchase online clothing
## 
##  Welch Two Sample t-test
## 
## data:  as.numeric(MainStudy$Q24) by MainStudy$UrbanLvl
## t = 0.097547, df = 151.91, p-value = 0.9224
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -0.06163199  0.06803404
## sample estimates:
## mean in group 1 mean in group 2 
##        1.045455        1.042254
summary(aov(as.numeric(Q24)~as.factor(MCLvl),MainStudy)) ## Purchase online clothing
##                   Df Sum Sq Mean Sq F value Pr(>F)
## as.factor(MCLvl)   2  0.007 0.00334   0.078  0.925
## Residuals        156  6.685 0.04285
t.test(as.numeric(MainStudy$Q24)~MainStudy$UrbanLvl) ## Purchase online clothing
## 
##  Welch Two Sample t-test
## 
## data:  as.numeric(MainStudy$Q24) by MainStudy$UrbanLvl
## t = 0.097547, df = 151.91, p-value = 0.9224
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -0.06163199  0.06803404
## sample estimates:
## mean in group 1 mean in group 2 
##        1.045455        1.042254
summary(aov(as.numeric(Q24)~as.factor(MCLvl),MainStudy)) ## Purchase online clothing
##                   Df Sum Sq Mean Sq F value Pr(>F)
## as.factor(MCLvl)   2  0.007 0.00334   0.078  0.925
## Residuals        156  6.685 0.04285
## chisq.test(MainStudy$UrbanLvl,MainStudy$Q25,simulate.p.value=T) ## Race-Ethinicity
## chisq.test(MainStudy$MCLvl,MainStudy$Q25,simulate.p.value=T) ## Race-Ethinicity

t.test(as.numeric(MainStudy$LocationLatitude)~MainStudy$UrbanLvl) ## LocatonLat
## 
##  Welch Two Sample t-test
## 
## data:  as.numeric(MainStudy$LocationLatitude) by MainStudy$UrbanLvl
## t = 0.82041, df = 144.5, p-value = 0.4133
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -1.168638  2.827240
## sample estimates:
## mean in group 1 mean in group 2 
##        38.40965        37.58035
summary(aov(as.numeric(LocationLatitude)~as.factor(MCLvl),MainStudy)) ## LocatonLat
##                   Df Sum Sq Mean Sq F value Pr(>F)
## as.factor(MCLvl)   2     73   36.70   0.931  0.396
## Residuals        156   6152   39.43
t.test(as.numeric(MainStudy$LocationLongitude)~MainStudy$UrbanLvl) ## LocatonLon
## 
##  Welch Two Sample t-test
## 
## data:  as.numeric(MainStudy$LocationLongitude) by MainStudy$UrbanLvl
## t = -1.1742, df = 101.35, p-value = 0.2431
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -15.854159   4.063811
## sample estimates:
## mean in group 1 mean in group 2 
##       -86.89086       -80.99569
summary(aov(as.numeric(LocationLongitude)~as.factor(MCLvl),MainStudy)) ## LocatonLon
##                   Df Sum Sq Mean Sq F value Pr(>F)
## as.factor(MCLvl)   2    312   156.1   0.175  0.839
## Residuals        156 138907   890.4
MainStudy[is.na(MainStudy)]<-0
MainStudy$StimuliTime<-MainStudy$Q32_Page.Submit+MainStudy$Q33_Page.Submit+
  MainStudy$Q34_Page.Submit+MainStudy$Q35_Page.Submit+MainStudy$Q36_Page.Submit+
  MainStudy$Q37_Page.Submit

t.test(as.numeric(MainStudy$StimuliTime)~MainStudy$UrbanLvl) ## StimuliTime
## 
##  Welch Two Sample t-test
## 
## data:  as.numeric(MainStudy$StimuliTime) by MainStudy$UrbanLvl
## t = -1.0162, df = 152.8, p-value = 0.3112
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -1.2685492  0.4068091
## sample estimates:
## mean in group 1 mean in group 2 
##        8.540045        8.970915
summary(aov(as.numeric(StimuliTime)~as.factor(MCLvl),MainStudy)) ## StimuliTime
##                   Df Sum Sq Mean Sq F value Pr(>F)
## as.factor(MCLvl)   2   10.2   5.101   0.712  0.492
## Residuals        156 1118.4   7.169
summary(lm(Auth~StimuliTime,MainStudy)) ## Does not affect Auth
## 
## Call:
## lm(formula = Auth ~ StimuliTime, data = MainStudy)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -3.5186 -1.2872 -0.0376  1.0105  4.6828 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  4.75070    0.46354  10.249   <2e-16 ***
## StimuliTime -0.02853    0.05077  -0.562    0.575    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.706 on 157 degrees of freedom
## Multiple R-squared:  0.002007,   Adjusted R-squared:  -0.00435 
## F-statistic: 0.3157 on 1 and 157 DF,  p-value: 0.575
## Reviewing groups in detail
aggregate(MainStudy$Auth,list(MainStudy$FL_17_DO),mean)
##   Group.1        x
## 1  Block1 4.856061
## 2  Block2 4.601562
## 3  Block3 4.978261
## 4  Block4 3.943182
## 5  Block5 4.596154
## 6  Block6 3.804348
aggregate(MainStudy$Auth,list(MainStudy$FL_17_DO),sd)
##   Group.1        x
## 1  Block1 1.646528
## 2  Block2 1.877133
## 3  Block3 2.123881
## 4  Block4 1.329455
## 5  Block5 1.600120
## 6  Block6 1.231584
MainStudyX<-subset(MainStudy,MainStudy$FL_17_DO=="Block1"|MainStudy$FL_17_DO=="Block4")
t.test(MainStudyX$Auth~MainStudyX$UrbanLvl) ## H1 works only for model 1
## 
##  Welch Two Sample t-test
## 
## data:  MainStudyX$Auth by MainStudyX$UrbanLvl
## t = 2.2646, df = 50.947, p-value = 0.02782
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  0.1035955 1.7221620
## sample estimates:
## mean in group 1 mean in group 2 
##        4.856061        3.943182
t.test(as.numeric(MainStudyX$Q26)~MainStudyX$UrbanLvl) ## Age is equivalent among groups
## 
##  Welch Two Sample t-test
## 
## data:  as.numeric(MainStudyX$Q26) by MainStudyX$UrbanLvl
## t = 2.6935, df = 51.674, p-value = 0.00951
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##   2.004482 13.722791
## sample estimates:
## mean in group 1 mean in group 2 
##        42.18182        34.31818
MainStudyX<-subset(MainStudy,MainStudy$FL_17_DO=="Block1"|MainStudy$FL_17_DO=="Block2"|MainStudy$FL_17_DO=="Block3")
summary(aov(Auth~as.factor(MCLvl),MainStudyX))
##                  Df Sum Sq Mean Sq F value Pr(>F)
## as.factor(MCLvl)  2   2.09   1.046   0.301  0.741
## Residuals        85 295.23   3.473
aov.out<-aov(Auth~as.factor(MCLvl),MainStudyX)
TukeyHSD(aov.out) 
##   Tukey multiple comparisons of means
##     95% family-wise confidence level
## 
## Fit: aov(formula = Auth ~ as.factor(MCLvl), data = MainStudyX)
## 
## $`as.factor(MCLvl)`
##           diff        lwr       upr     p adj
## 2-1 -0.2544981 -1.3574663 0.8484701 0.8465425
## 3-1  0.1222003 -1.0853672 1.3297677 0.9683990
## 3-2  0.3766984 -0.8385938 1.5919906 0.7408095
summary(lm(Auth~MCLvl,MainStudyX)) ## H2 partially works only for background 1
## 
## Call:
## lm(formula = Auth ~ MCLvl, data = MainStudyX)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -3.8402 -1.3000 -0.0902  1.0326  4.2000 
## 
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  4.71966    0.51326   9.195 1.97e-14 ***
## MCLvl        0.04018    0.25099   0.160    0.873    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 1.859 on 86 degrees of freedom
## Multiple R-squared:  0.0002979,  Adjusted R-squared:  -0.01133 
## F-statistic: 0.02563 on 1 and 86 DF,  p-value: 0.8732
summary(aov(as.numeric(Q26)~as.factor(MCLvl),MainStudy)) ## Age is equivalent among groups
##                   Df Sum Sq Mean Sq F value Pr(>F)
## as.factor(MCLvl)   2    147    73.3   0.555  0.575
## Residuals        156  20598   132.0
## Location of the sample
map(database="world", ylim=c(36,40), xlim=c(-99,-95), col="white", fill=TRUE, projection="gilbert", orientation= c(90,0,225))
lon<-as.character(MainStudy$LocationLongitude)
lat<-as.character(MainStudy$LocationLatitude)
coord<-mapproject(lon, lat, proj="gilbert", orientation=c(90, 0, 225))
points(coord, pch=20, cex=0.8, col="black")