1. Summary of Walmart Data

Stores were initially categorized by number rather than by StoreID

##      Store        Date            Weekly_Sales      Holiday_Flag    
##  Min.   : 1   Length:6435        Min.   : 209986   Min.   :0.00000  
##  1st Qu.:12   Class :character   1st Qu.: 553350   1st Qu.:0.00000  
##  Median :23   Mode  :character   Median : 960746   Median :0.00000  
##  Mean   :23                      Mean   :1046965   Mean   :0.06993  
##  3rd Qu.:34                      3rd Qu.:1420159   3rd Qu.:0.00000  
##  Max.   :45                      Max.   :3818686   Max.   :1.00000  
##   Temperature       Fuel_Price         CPI         Unemployment   
##  Min.   : -2.06   Min.   :2.472   Min.   :126.1   Min.   : 3.879  
##  1st Qu.: 47.46   1st Qu.:2.933   1st Qu.:131.7   1st Qu.: 6.891  
##  Median : 62.67   Median :3.445   Median :182.6   Median : 7.874  
##  Mean   : 60.66   Mean   :3.359   Mean   :171.6   Mean   : 7.999  
##  3rd Qu.: 74.94   3rd Qu.:3.735   3rd Qu.:212.7   3rd Qu.: 8.622  
##  Max.   :100.14   Max.   :4.468   Max.   :227.2   Max.   :14.313

2. Splitting data into training and validation data

##      Store          Date            Weekly_Sales     Holiday_Flag
##  1      : 143   Length:6435        Min.   : 209986   0:5985      
##  2      : 143   Class :character   1st Qu.: 553350   1: 450      
##  3      : 143   Mode  :character   Median : 960746               
##  4      : 143                      Mean   :1046965               
##  5      : 143                      3rd Qu.:1420159               
##  6      : 143                      Max.   :3818686               
##  (Other):5577                                                    
##   Temperature       Fuel_Price         CPI         Unemployment   
##  Min.   : -2.06   Min.   :2.472   Min.   :126.1   Min.   : 3.879  
##  1st Qu.: 47.46   1st Qu.:2.933   1st Qu.:131.7   1st Qu.: 6.891  
##  Median : 62.67   Median :3.445   Median :182.6   Median : 7.874  
##  Mean   : 60.66   Mean   :3.359   Mean   :171.6   Mean   : 7.999  
##  3rd Qu.: 74.94   3rd Qu.:3.735   3rd Qu.:212.7   3rd Qu.: 8.622  
##  Max.   :100.14   Max.   :4.468   Max.   :227.2   Max.   :14.313  
##                                                                   
##      random         
##  Min.   :0.0000049  
##  1st Qu.:0.2553981  
##  Median :0.4990746  
##  Mean   :0.5017721  
##  3rd Qu.:0.7480154  
##  Max.   :0.9999758  
## 
## tibble [6,435 × 9] (S3: tbl_df/tbl/data.frame)
##  $ Store       : Factor w/ 45 levels "1","2","3","4",..: 1 1 1 1 1 1 1 1 1 1 ...
##  $ Date        : chr [1:6435] "05-02-2010" "12-02-2010" "19-02-2010" "26-02-2010" ...
##  $ Weekly_Sales: num [1:6435] 1643691 1641957 1611968 1409728 1554807 ...
##  $ Holiday_Flag: Factor w/ 2 levels "0","1": 1 2 1 1 1 1 1 1 1 1 ...
##  $ Temperature : num [1:6435] 42.3 38.5 39.9 46.6 46.5 ...
##  $ Fuel_Price  : num [1:6435] 2.57 2.55 2.51 2.56 2.62 ...
##  $ CPI         : num [1:6435] 211 211 211 211 211 ...
##  $ Unemployment: num [1:6435] 8.11 8.11 8.11 8.11 8.11 ...
##  $ random      : num [1:6435] 0.118 0.632 0.386 0.935 0.973 ...

##      Min.   1st Qu.    Median      Mean   3rd Qu.      Max. 
## 0.0000049 0.2553981 0.4990746 0.5017721 0.7480154 0.9999758

3. Creating model and checking results

Important At the bottom of the data is R-squared percentage which tells us how correlated the data is.

## 
## Call:
## lm(formula = Weekly_Sales ~ . - Date, data = trainlm)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -525229  -70856  -12219   39316 1842323 
## 
## Coefficients:
##                 Estimate Std. Error t value Pr(>|t|)    
## (Intercept)    1067528.3   278137.5   3.838 0.000126 ***
## Store2          364064.7    23341.2  15.598  < 2e-16 ***
## Store3        -1173377.2    24044.0 -48.801  < 2e-16 ***
## Store4          850034.7   116869.9   7.273 4.12e-13 ***
## Store5        -1268813.7    23933.2 -53.015  < 2e-16 ***
## Store6          -22077.1    23418.4  -0.943 0.345872    
## Store7         -894243.5    35735.5 -25.024  < 2e-16 ***
## Store8         -697747.6    24663.8 -28.290  < 2e-16 ***
## Store9        -1057109.2    24036.2 -43.980  < 2e-16 ***
## Store10         724913.8   112912.8   6.420 1.50e-10 ***
## Store11        -214922.0    23387.3  -9.190  < 2e-16 ***
## Store12         -69289.1   106126.8  -0.653 0.513861    
## Store13         780241.1   114462.2   6.817 1.06e-11 ***
## Store14         600211.4    43394.5  13.832  < 2e-16 ***
## Store15        -607907.2   106088.8  -5.730 1.07e-08 ***
## Store16        -988525.2    39413.8 -25.081  < 2e-16 ***
## Store17        -361391.4   115449.4  -3.130 0.001758 ** 
## Store18        -154947.9   103382.9  -1.499 0.134002    
## Store19         213743.8   106007.2   2.016 0.043827 *  
## Store20         590819.2    25339.2  23.316  < 2e-16 ***
## Store21        -796391.1    22989.0 -34.642  < 2e-16 ***
## Store22        -224400.7   100135.5  -2.241 0.025077 *  
## Store23          95265.3   112962.3   0.843 0.399085    
## Store24         137157.7   104799.3   1.309 0.190681    
## Store25        -837307.3    25270.2 -33.134  < 2e-16 ***
## Store26        -238478.4   105553.2  -2.259 0.023911 *  
## Store27         532878.9   100870.5   5.283 1.33e-07 ***
## Store28         241476.4   105869.7   2.281 0.022602 *  
## Store29        -651373.6   101765.4  -6.401 1.71e-10 ***
## Store30       -1111159.0    23120.6 -48.059  < 2e-16 ***
## Store31        -160870.7    23347.8  -6.890 6.35e-12 ***
## Store32        -285658.4    35031.9  -8.154 4.52e-16 ***
## Store33        -908025.0   112539.7  -8.068 9.07e-16 ***
## Store34        -206277.0   108100.3  -1.908 0.056429 .  
## Store35        -311665.5    98829.5  -3.154 0.001624 ** 
## Store36       -1162570.1    23361.8 -49.764  < 2e-16 ***
## Store37       -1020966.4    23293.5 -43.831  < 2e-16 ***
## Store38        -692425.7   106024.5  -6.531 7.27e-11 ***
## Store39         -95946.6    22948.3  -4.181 2.96e-05 ***
## Store40        -346137.1   112863.2  -3.067 0.002176 ** 
## Store41        -227367.1    37895.4  -6.000 2.13e-09 ***
## Store42        -624190.0   112745.8  -5.536 3.27e-08 ***
## Store43        -839268.2    26464.2 -31.713  < 2e-16 ***
## Store44        -937498.8   115260.5  -8.134 5.34e-16 ***
## Store45        -626669.3    43375.9 -14.447  < 2e-16 ***
## Holiday_Flag1    63494.5     9744.2   6.516 8.01e-11 ***
## Temperature       -869.9      160.5  -5.421 6.23e-08 ***
## Fuel_Price      -45542.2     8656.9  -5.261 1.50e-07 ***
## CPI               3930.9     1258.1   3.124 0.001793 ** 
## Unemployment    -20865.8     5265.2  -3.963 7.52e-05 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 162900 on 4468 degrees of freedom
## Multiple R-squared:  0.9178, Adjusted R-squared:  0.9169 
## F-statistic:  1019 on 49 and 4468 DF,  p-value: < 2.2e-16

4. Creating new model with backward selection

Important: With backward selection, you remove certain sections of the data to make r^2 more precise. In this instance, no data was removed.

## Backward Elimination Method 
## ---------------------------
## 
## Candidate Terms: 
## 
## 1. Store 
## 2. Holiday_Flag 
## 3. Temperature 
## 4. Fuel_Price 
## 5. CPI 
## 6. Unemployment 
## 
## 
## Step   => 0 
## Model  => Weekly_Sales ~ Store + Holiday_Flag + Temperature + Fuel_Price + CPI + Unemployment 
## R2     => 0.918 
## 
## Initiating stepwise selection... 
## 
## 
## No more variables to be removed.
## 
## Call:
## lm(formula = paste(response, "~", paste(c(include, cterms), collapse = " + ")), 
##     data = l)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -525229  -70856  -12219   39316 1842323 
## 
## Coefficients:
##                 Estimate Std. Error t value Pr(>|t|)    
## (Intercept)    1067528.3   278137.5   3.838 0.000126 ***
## Store2          364064.7    23341.2  15.598  < 2e-16 ***
## Store3        -1173377.2    24044.0 -48.801  < 2e-16 ***
## Store4          850034.7   116869.9   7.273 4.12e-13 ***
## Store5        -1268813.7    23933.2 -53.015  < 2e-16 ***
## Store6          -22077.1    23418.4  -0.943 0.345872    
## Store7         -894243.5    35735.5 -25.024  < 2e-16 ***
## Store8         -697747.6    24663.8 -28.290  < 2e-16 ***
## Store9        -1057109.2    24036.2 -43.980  < 2e-16 ***
## Store10         724913.8   112912.8   6.420 1.50e-10 ***
## Store11        -214922.0    23387.3  -9.190  < 2e-16 ***
## Store12         -69289.1   106126.8  -0.653 0.513861    
## Store13         780241.1   114462.2   6.817 1.06e-11 ***
## Store14         600211.4    43394.5  13.832  < 2e-16 ***
## Store15        -607907.2   106088.8  -5.730 1.07e-08 ***
## Store16        -988525.2    39413.8 -25.081  < 2e-16 ***
## Store17        -361391.4   115449.4  -3.130 0.001758 ** 
## Store18        -154947.9   103382.9  -1.499 0.134002    
## Store19         213743.8   106007.2   2.016 0.043827 *  
## Store20         590819.2    25339.2  23.316  < 2e-16 ***
## Store21        -796391.1    22989.0 -34.642  < 2e-16 ***
## Store22        -224400.7   100135.5  -2.241 0.025077 *  
## Store23          95265.3   112962.3   0.843 0.399085    
## Store24         137157.7   104799.3   1.309 0.190681    
## Store25        -837307.3    25270.2 -33.134  < 2e-16 ***
## Store26        -238478.4   105553.2  -2.259 0.023911 *  
## Store27         532878.9   100870.5   5.283 1.33e-07 ***
## Store28         241476.4   105869.7   2.281 0.022602 *  
## Store29        -651373.6   101765.4  -6.401 1.71e-10 ***
## Store30       -1111159.0    23120.6 -48.059  < 2e-16 ***
## Store31        -160870.7    23347.8  -6.890 6.35e-12 ***
## Store32        -285658.4    35031.9  -8.154 4.52e-16 ***
## Store33        -908025.0   112539.7  -8.068 9.07e-16 ***
## Store34        -206277.0   108100.3  -1.908 0.056429 .  
## Store35        -311665.5    98829.5  -3.154 0.001624 ** 
## Store36       -1162570.1    23361.8 -49.764  < 2e-16 ***
## Store37       -1020966.4    23293.5 -43.831  < 2e-16 ***
## Store38        -692425.7   106024.5  -6.531 7.27e-11 ***
## Store39         -95946.6    22948.3  -4.181 2.96e-05 ***
## Store40        -346137.1   112863.2  -3.067 0.002176 ** 
## Store41        -227367.1    37895.4  -6.000 2.13e-09 ***
## Store42        -624190.0   112745.8  -5.536 3.27e-08 ***
## Store43        -839268.2    26464.2 -31.713  < 2e-16 ***
## Store44        -937498.8   115260.5  -8.134 5.34e-16 ***
## Store45        -626669.3    43375.9 -14.447  < 2e-16 ***
## Holiday_Flag1    63494.5     9744.2   6.516 8.01e-11 ***
## Temperature       -869.9      160.5  -5.421 6.23e-08 ***
## Fuel_Price      -45542.2     8656.9  -5.261 1.50e-07 ***
## CPI               3930.9     1258.1   3.124 0.001793 ** 
## Unemployment    -20865.8     5265.2  -3.963 7.52e-05 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 162900 on 4468 degrees of freedom
## Multiple R-squared:  0.9178, Adjusted R-squared:  0.9169 
## F-statistic:  1019 on 49 and 4468 DF,  p-value: < 2.2e-16

5. Model with interactions (with backward selection)

## 
## Call:
## lm(formula = Weekly_Sales ~ (. - Date)^2, data = trainlm)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -608696  -57493   -8887   33878 1670847 
## 
## Coefficients:
##                              Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                -1.814e+07  8.304e+06  -2.184 0.028989 *  
## Store2                      3.745e+06  5.715e+06   0.655 0.512310    
## Store3                      2.851e+06  3.866e+06   0.737 0.460921    
## Store4                      3.465e+06  7.708e+06   0.450 0.653092    
## Store5                      1.679e+06  3.960e+06   0.424 0.671550    
## Store6                     -1.064e+07  4.181e+06  -2.544 0.010997 *  
## Store7                     -6.467e+06  4.638e+06  -1.394 0.163305    
## Store8                      1.356e+06  3.793e+06   0.358 0.720734    
## Store9                      2.035e+06  4.314e+06   0.472 0.637161    
## Store10                     1.241e+07  6.838e+06   1.815 0.069632 .  
## Store11                    -2.402e+06  3.893e+06  -0.617 0.537244    
## Store12                     4.373e+06  5.172e+06   0.845 0.397921    
## Store13                     2.009e+07  8.994e+06   2.233 0.025570 *  
## Store14                     9.701e+06  3.065e+06   3.165 0.001561 ** 
## Store15                     9.128e+06  3.958e+06   2.306 0.021146 *  
## Store16                     3.696e+06  4.658e+06   0.794 0.427527    
## Store17                     9.953e+06  5.563e+06   1.789 0.073639 .  
## Store18                     1.335e+07  5.186e+06   2.573 0.010105 *  
## Store19                     6.876e+06  3.975e+06   1.730 0.083737 .  
## Store20                     4.736e+06  2.857e+06   1.657 0.097520 .  
## Store21                    -4.378e+06  4.965e+06  -0.882 0.377875    
## Store22                     4.923e+06  5.151e+06   0.956 0.339218    
## Store23                     8.971e+06  7.185e+06   1.249 0.211908    
## Store24                     5.695e+06  4.014e+06   1.419 0.156086    
## Store25                     1.529e+06  2.828e+06   0.541 0.588849    
## Store26                     6.019e+06  6.690e+06   0.900 0.368314    
## Store27                     1.016e+07  3.815e+06   2.664 0.007747 ** 
## Store28                     5.151e+06  4.947e+06   1.041 0.297822    
## Store29                     5.784e+06  4.701e+06   1.230 0.218598    
## Store30                     5.154e+06  5.512e+06   0.935 0.349764    
## Store31                    -7.961e+06  5.504e+06  -1.446 0.148143    
## Store32                    -7.065e+06  4.495e+06  -1.572 0.116092    
## Store33                     8.404e+06  7.090e+06   1.185 0.235985    
## Store34                     4.043e+06  4.347e+06   0.930 0.352365    
## Store35                     8.911e+06  3.632e+06   2.453 0.014195 *  
## Store36                     7.620e+06  5.564e+06   1.370 0.170902    
## Store37                     3.988e+06  5.224e+06   0.763 0.445333    
## Store38                     5.311e+06  5.566e+06   0.954 0.340050    
## Store39                    -1.349e+07  4.930e+06  -2.735 0.006260 ** 
## Store40                     1.030e+07  7.184e+06   1.434 0.151649    
## Store41                    -2.191e+06  5.574e+06  -0.393 0.694231    
## Store42                     1.148e+07  7.104e+06   1.616 0.106188    
## Store43                     4.200e+06  3.262e+06   1.287 0.198006    
## Store44                     1.257e+07  1.002e+07   1.255 0.209578    
## Store45                     2.409e+06  2.961e+06   0.813 0.415989    
## Holiday_Flag1               4.483e+05  1.199e+06   0.374 0.708591    
## Temperature                 6.296e+04  2.018e+04   3.120 0.001822 ** 
## Fuel_Price                  2.753e+06  9.577e+05   2.875 0.004059 ** 
## CPI                         9.075e+04  3.870e+04   2.345 0.019078 *  
## Unemployment                4.772e+05  9.168e+05   0.521 0.602736    
## Store2:Holiday_Flag1        6.946e+04  8.315e+04   0.835 0.403556    
## Store3:Holiday_Flag1       -9.540e+04  8.601e+04  -1.109 0.267440    
## Store4:Holiday_Flag1       -8.546e+04  5.139e+05  -0.166 0.867929    
## Store5:Holiday_Flag1       -9.569e+04  8.144e+04  -1.175 0.240080    
## Store6:Holiday_Flag1        8.985e+03  8.291e+04   0.108 0.913707    
## Store7:Holiday_Flag1        1.893e+05  1.507e+05   1.256 0.209100    
## Store8:Holiday_Flag1       -3.538e+04  9.581e+04  -0.369 0.711986    
## Store9:Holiday_Flag1       -9.178e+04  9.408e+04  -0.976 0.329311    
## Store10:Holiday_Flag1       9.823e+04  5.111e+05   0.192 0.847587    
## Store11:Holiday_Flag1      -4.844e+04  8.481e+04  -0.571 0.567882    
## Store12:Holiday_Flag1       4.047e+05  5.017e+05   0.807 0.419873    
## Store13:Holiday_Flag1       6.337e+04  5.111e+05   0.124 0.901339    
## Store14:Holiday_Flag1       1.527e+05  1.926e+05   0.793 0.427737    
## Store15:Holiday_Flag1       1.361e+05  4.811e+05   0.283 0.777299    
## Store16:Holiday_Flag1      -2.137e+04  1.586e+05  -0.135 0.892802    
## Store17:Holiday_Flag1       9.680e+04  5.139e+05   0.188 0.850600    
## Store18:Holiday_Flag1       9.925e+04  4.708e+05   0.211 0.833056    
## Store19:Holiday_Flag1       2.178e+05  4.819e+05   0.452 0.651368    
## Store20:Holiday_Flag1      -7.711e+03  9.687e+04  -0.080 0.936554    
## Store21:Holiday_Flag1      -5.643e+04  8.238e+04  -0.685 0.493360    
## Store22:Holiday_Flag1       1.157e+05  4.516e+05   0.256 0.797865    
## Store23:Holiday_Flag1      -1.219e+05  4.970e+05  -0.245 0.806334    
## Store24:Holiday_Flag1       2.224e+05  4.769e+05   0.466 0.641017    
## Store25:Holiday_Flag1       5.064e+04  9.499e+04   0.533 0.593964    
## Store26:Holiday_Flag1       1.896e+05  4.778e+05   0.397 0.691606    
## Store27:Holiday_Flag1       2.864e+05  4.584e+05   0.625 0.532116    
## Store28:Holiday_Flag1       4.544e+05  5.012e+05   0.907 0.364652    
## Store29:Holiday_Flag1       2.693e+05  4.688e+05   0.575 0.565632    
## Store30:Holiday_Flag1      -4.589e+04  8.614e+04  -0.533 0.594217    
## Store31:Holiday_Flag1       5.478e+04  8.321e+04   0.658 0.510336    
## Store32:Holiday_Flag1       8.669e+04  1.484e+05   0.584 0.559048    
## Store33:Holiday_Flag1       5.629e+04  5.120e+05   0.110 0.912457    
## Store34:Holiday_Flag1       2.762e+05  4.951e+05   0.558 0.576983    
## Store35:Holiday_Flag1       2.126e+05  4.494e+05   0.473 0.636087    
## Store36:Holiday_Flag1      -3.544e+04  9.980e+04  -0.355 0.722562    
## Store37:Holiday_Flag1      -4.067e+04  9.842e+04  -0.413 0.679454    
## Store38:Holiday_Flag1       3.685e+05  4.995e+05   0.738 0.460724    
## Store39:Holiday_Flag1      -8.082e+03  7.846e+04  -0.103 0.917959    
## Store40:Holiday_Flag1      -1.057e+05  4.963e+05  -0.213 0.831429    
## Store41:Holiday_Flag1      -1.351e+04  1.528e+05  -0.088 0.929544    
## Store42:Holiday_Flag1       6.628e+04  5.110e+05   0.130 0.896811    
## Store43:Holiday_Flag1       1.529e+05  1.255e+05   1.219 0.223017    
## Store44:Holiday_Flag1      -2.872e+04  5.109e+05  -0.056 0.955176    
## Store45:Holiday_Flag1       7.457e+04  1.948e+05   0.383 0.701931    
## Store2:Temperature         -3.912e+02  1.581e+03  -0.247 0.804545    
## Store3:Temperature          1.552e+03  1.830e+03   0.848 0.396450    
## Store4:Temperature         -3.122e+04  8.565e+03  -3.646 0.000270 ***
## Store5:Temperature          1.476e+03  1.740e+03   0.848 0.396619    
## Store6:Temperature          1.978e+03  1.669e+03   1.185 0.236125    
## Store7:Temperature         -2.494e+03  2.549e+03  -0.978 0.327921    
## Store8:Temperature          9.016e+02  1.694e+03   0.532 0.594494    
## Store9:Temperature          1.815e+03  1.689e+03   1.075 0.282652    
## Store10:Temperature        -3.391e+04  8.405e+03  -4.035 5.57e-05 ***
## Store11:Temperature        -4.923e+02  1.785e+03  -0.276 0.782708    
## Store12:Temperature        -2.501e+04  8.039e+03  -3.111 0.001877 ** 
## Store13:Temperature        -2.832e+04  8.452e+03  -3.351 0.000814 ***
## Store14:Temperature        -1.010e+04  3.220e+03  -3.136 0.001724 ** 
## Store15:Temperature        -2.312e+04  7.850e+03  -2.945 0.003242 ** 
## Store16:Temperature        -3.331e+03  2.729e+03  -1.221 0.222238    
## Store17:Temperature        -2.514e+04  8.494e+03  -2.960 0.003095 ** 
## Store18:Temperature        -2.111e+04  7.718e+03  -2.735 0.006267 ** 
## Store19:Temperature        -2.223e+04  7.843e+03  -2.834 0.004616 ** 
## Store20:Temperature        -5.481e+03  1.681e+03  -3.260 0.001121 ** 
## Store21:Temperature         1.342e+03  1.595e+03   0.841 0.400196    
## Store22:Temperature        -2.189e+04  7.414e+03  -2.953 0.003168 ** 
## Store23:Temperature        -2.540e+04  8.192e+03  -3.101 0.001943 ** 
## Store24:Temperature        -2.092e+04  7.761e+03  -2.696 0.007055 ** 
## Store25:Temperature         1.084e+03  1.689e+03   0.642 0.521096    
## Store26:Temperature        -2.126e+04  7.828e+03  -2.716 0.006635 ** 
## Store27:Temperature        -1.804e+04  7.462e+03  -2.417 0.015689 *  
## Store28:Temperature        -2.407e+04  8.020e+03  -3.001 0.002705 ** 
## Store29:Temperature        -2.255e+04  7.611e+03  -2.963 0.003065 ** 
## Store30:Temperature         2.162e+03  1.598e+03   1.353 0.176118    
## Store31:Temperature         1.691e+03  1.589e+03   1.064 0.287272    
## Store32:Temperature        -4.207e+03  2.464e+03  -1.707 0.087869 .  
## Store33:Temperature        -2.488e+04  8.365e+03  -2.975 0.002949 ** 
## Store34:Temperature        -2.424e+04  8.039e+03  -3.015 0.002581 ** 
## Store35:Temperature        -1.850e+04  7.331e+03  -2.523 0.011656 *  
## Store36:Temperature         2.826e+03  1.848e+03   1.529 0.126313    
## Store37:Temperature         1.477e+03  1.894e+03   0.780 0.435486    
## Store38:Temperature        -2.176e+04  8.028e+03  -2.711 0.006735 ** 
## Store39:Temperature         3.773e+03  1.752e+03   2.153 0.031377 *  
## Store40:Temperature        -2.408e+04  8.191e+03  -2.939 0.003307 ** 
## Store41:Temperature        -3.125e+03  2.620e+03  -1.193 0.232999    
## Store42:Temperature        -2.539e+04  8.390e+03  -3.026 0.002494 ** 
## Store43:Temperature         2.110e+03  1.882e+03   1.121 0.262342    
## Store44:Temperature        -2.558e+04  8.520e+03  -3.002 0.002695 ** 
## Store45:Temperature        -8.667e+03  3.194e+03  -2.713 0.006687 ** 
## Store2:Fuel_Price          -1.269e+05  9.679e+04  -1.311 0.189999    
## Store3:Fuel_Price           8.265e+04  1.057e+05   0.782 0.434304    
## Store4:Fuel_Price          -1.251e+06  3.696e+05  -3.385 0.000719 ***
## Store5:Fuel_Price          -1.991e+03  9.473e+04  -0.021 0.983233    
## Store6:Fuel_Price          -1.444e+05  8.997e+04  -1.605 0.108480    
## Store7:Fuel_Price          -2.514e+05  1.209e+05  -2.080 0.037557 *  
## Store8:Fuel_Price           3.823e+04  9.722e+04   0.393 0.694174    
## Store9:Fuel_Price           6.005e+04  9.864e+04   0.609 0.542726    
## Store10:Fuel_Price         -1.214e+06  3.514e+05  -3.455 0.000556 ***
## Store11:Fuel_Price         -6.151e+04  1.057e+05  -0.582 0.560518    
## Store12:Fuel_Price         -1.104e+06  3.266e+05  -3.379 0.000734 ***
## Store13:Fuel_Price         -1.035e+06  3.716e+05  -2.785 0.005373 ** 
## Store14:Fuel_Price         -3.837e+05  1.430e+05  -2.683 0.007319 ** 
## Store15:Fuel_Price         -9.405e+05  3.353e+05  -2.805 0.005052 ** 
## Store16:Fuel_Price         -3.300e+05  1.480e+05  -2.229 0.025876 *  
## Store17:Fuel_Price         -1.016e+06  3.750e+05  -2.708 0.006797 ** 
## Store18:Fuel_Price         -1.122e+06  3.225e+05  -3.478 0.000510 ***
## Store19:Fuel_Price         -1.222e+06  3.331e+05  -3.668 0.000248 ***
## Store20:Fuel_Price         -1.871e+05  9.328e+04  -2.006 0.044914 *  
## Store21:Fuel_Price         -5.882e+04  9.125e+04  -0.645 0.519188    
## Store22:Fuel_Price         -9.976e+05  3.142e+05  -3.175 0.001509 ** 
## Store23:Fuel_Price         -1.182e+06  3.667e+05  -3.222 0.001281 ** 
## Store24:Fuel_Price         -1.130e+06  3.294e+05  -3.431 0.000607 ***
## Store25:Fuel_Price         -1.378e+05  9.620e+04  -1.433 0.152002    
## Store26:Fuel_Price         -1.023e+06  3.337e+05  -3.064 0.002195 ** 
## Store27:Fuel_Price         -1.077e+06  3.176e+05  -3.391 0.000702 ***
## Store28:Fuel_Price         -1.146e+06  3.270e+05  -3.505 0.000462 ***
## Store29:Fuel_Price         -1.018e+06  3.136e+05  -3.247 0.001174 ** 
## Store30:Fuel_Price          1.481e+04  9.235e+04   0.160 0.872603    
## Store31:Fuel_Price         -6.887e+04  9.400e+04  -0.733 0.463820    
## Store32:Fuel_Price         -2.255e+05  1.179e+05  -1.913 0.055769 .  
## Store33:Fuel_Price         -1.108e+06  3.493e+05  -3.173 0.001522 ** 
## Store34:Fuel_Price         -1.207e+06  3.405e+05  -3.545 0.000396 ***
## Store35:Fuel_Price         -9.228e+05  3.137e+05  -2.941 0.003287 ** 
## Store36:Fuel_Price          1.435e+04  9.813e+04   0.146 0.883720    
## Store37:Fuel_Price          3.679e+04  1.015e+05   0.362 0.717090    
## Store38:Fuel_Price         -1.056e+06  3.290e+05  -3.211 0.001334 ** 
## Store39:Fuel_Price         -1.677e+05  9.572e+04  -1.753 0.079754 .  
## Store40:Fuel_Price         -1.120e+06  3.670e+05  -3.051 0.002297 ** 
## Store41:Fuel_Price         -1.945e+05  1.329e+05  -1.463 0.143579    
## Store42:Fuel_Price         -1.091e+06  3.524e+05  -3.097 0.001968 ** 
## Store43:Fuel_Price         -2.144e+04  1.176e+05  -0.182 0.855326    
## Store44:Fuel_Price         -1.065e+06  3.793e+05  -2.808 0.005012 ** 
## Store45:Fuel_Price         -3.645e+05  1.425e+05  -2.558 0.010569 *  
## Store2:CPI                 -1.157e+04  2.267e+04  -0.510 0.609771    
## Store3:CPI                 -1.703e+04  1.533e+04  -1.110 0.266874    
## Store4:CPI                  4.691e+04  4.543e+04   1.033 0.301784    
## Store5:CPI                 -1.232e+04  1.579e+04  -0.780 0.435324    
## Store6:CPI                  4.137e+04  1.666e+04   2.483 0.013082 *  
## Store7:CPI                  2.816e+04  1.878e+04   1.499 0.133898    
## Store8:CPI                 -9.328e+03  1.532e+04  -0.609 0.542772    
## Store9:CPI                 -1.409e+04  1.756e+04  -0.803 0.422121    
## Store10:CPI                -2.169e+04  4.266e+04  -0.508 0.611210    
## Store11:CPI                 9.009e+03  1.550e+04   0.581 0.561189    
## Store12:CPI                 2.052e+04  4.338e+04   0.473 0.636195    
## Store13:CPI                -8.289e+04  5.865e+04  -1.413 0.157597    
## Store14:CPI                -3.856e+04  1.208e+04  -3.193 0.001419 ** 
## Store15:CPI                -3.388e+04  1.788e+04  -1.895 0.058103 .  
## Store16:CPI                -1.172e+04  1.728e+04  -0.678 0.497578    
## Store17:CPI                -2.130e+04  2.564e+04  -0.831 0.406063    
## Store18:CPI                -3.559e+04  2.695e+04  -1.320 0.186747    
## Store19:CPI                 1.369e+04  1.785e+04   0.767 0.443074    
## Store20:CPI                -8.131e+03  1.094e+04  -0.744 0.457211    
## Store21:CPI                 1.222e+04  1.967e+04   0.621 0.534444    
## Store22:CPI                 4.403e+03  2.408e+04   0.183 0.854909    
## Store23:CPI                -5.547e+03  3.462e+04  -0.160 0.872722    
## Store24:CPI                 1.734e+04  2.352e+04   0.737 0.461109    
## Store25:CPI                -6.674e+03  1.102e+04  -0.606 0.544848    
## Store26:CPI                 1.411e+03  3.098e+04   0.046 0.963676    
## Store27:CPI                -1.838e+04  1.796e+04  -1.023 0.306220    
## Store28:CPI                 1.674e+04  4.169e+04   0.402 0.688019    
## Store29:CPI                -4.391e+02  2.611e+04  -0.017 0.986585    
## Store30:CPI                -2.570e+04  2.172e+04  -1.183 0.236762    
## Store31:CPI                 3.001e+04  2.177e+04   1.378 0.168132    
## Store32:CPI                 3.144e+04  1.845e+04   1.704 0.088534 .  
## Store33:CPI                -1.464e+04  4.541e+04  -0.322 0.747101    
## Store34:CPI                 2.515e+04  2.613e+04   0.963 0.335736    
## Store35:CPI                -5.167e+04  1.732e+04  -2.984 0.002863 ** 
## Store36:CPI                -3.804e+04  2.266e+04  -1.679 0.093204 .  
## Store37:CPI                -2.101e+04  2.139e+04  -0.982 0.326018    
## Store38:CPI                 8.277e+03  4.596e+04   0.180 0.857083    
## Store39:CPI                 5.716e+04  2.000e+04   2.858 0.004284 ** 
## Store40:CPI                -2.000e+04  3.444e+04  -0.581 0.561540    
## Store41:CPI                 1.469e+04  2.158e+04   0.681 0.496129    
## Store42:CPI                -3.227e+04  4.466e+04  -0.723 0.470009    
## Store43:CPI                -1.921e+04  1.533e+04  -1.253 0.210268    
## Store44:CPI                -4.390e+04  6.762e+04  -0.649 0.516169    
## Store45:CPI                -6.593e+03  1.195e+04  -0.552 0.581053    
## Store2:Unemployment        -5.909e+04  1.425e+05  -0.415 0.678399    
## Store3:Unemployment        -9.181e+04  1.170e+05  -0.785 0.432548    
## Store4:Unemployment        -2.214e+05  4.056e+05  -0.546 0.585198    
## Store5:Unemployment        -4.730e+04  1.269e+05  -0.373 0.709430    
## Store6:Unemployment         2.994e+05  1.212e+05   2.471 0.013503 *  
## Store7:Unemployment         1.484e+05  1.741e+05   0.852 0.394056    
## Store8:Unemployment        -2.504e+04  1.283e+05  -0.195 0.845239    
## Store9:Unemployment        -4.403e+04  1.282e+05  -0.343 0.731328    
## Store10:Unemployment       -2.269e+05  4.130e+05  -0.549 0.582780    
## Store11:Unemployment        6.225e+04  1.166e+05   0.534 0.593520    
## Store12:Unemployment       -1.591e+05  4.086e+05  -0.389 0.697038    
## Store13:Unemployment       -3.474e+05  4.125e+05  -0.842 0.399663    
## Store14:Unemployment        2.032e+04  2.390e+05   0.085 0.932255    
## Store15:Unemployment        1.896e+04  4.022e+05   0.047 0.962397    
## Store16:Unemployment       -1.131e+05  2.083e+05  -0.543 0.587163    
## Store17:Unemployment       -2.275e+05  4.094e+05  -0.556 0.578570    
## Store18:Unemployment       -3.422e+05  3.895e+05  -0.879 0.379643    
## Store19:Unemployment       -2.815e+05  3.996e+05  -0.704 0.481180    
## Store20:Unemployment       -1.917e+05  1.224e+05  -1.566 0.117391    
## Store21:Unemployment        1.379e+05  1.258e+05   1.096 0.272943    
## Store22:Unemployment       -4.569e+04  3.775e+05  -0.121 0.903676    
## Store23:Unemployment       -2.506e+05  4.091e+05  -0.613 0.540226    
## Store24:Unemployment       -2.526e+05  3.916e+05  -0.645 0.519013    
## Store25:Unemployment       -6.442e+04  1.173e+05  -0.549 0.582794    
## Store26:Unemployment       -1.142e+05  4.282e+05  -0.267 0.789753    
## Store27:Unemployment       -2.021e+05  3.824e+05  -0.528 0.597302    
## Store28:Unemployment       -1.516e+05  4.092e+05  -0.371 0.710989    
## Store29:Unemployment       -1.217e+05  3.859e+05  -0.315 0.752495    
## Store30:Unemployment       -1.202e+05  1.399e+05  -0.860 0.390044    
## Store31:Unemployment        1.877e+05  1.386e+05   1.355 0.175647    
## Store32:Unemployment        2.134e+05  1.654e+05   1.290 0.197137    
## Store33:Unemployment       -1.765e+05  4.120e+05  -0.428 0.668461    
## Store34:Unemployment       -1.569e+05  4.054e+05  -0.387 0.698808    
## Store35:Unemployment        3.127e+05  3.835e+05   0.816 0.414792    
## Store36:Unemployment       -1.096e+05  1.242e+05  -0.882 0.377613    
## Store37:Unemployment       -9.141e+04  1.177e+05  -0.776 0.437567    
## Store38:Unemployment       -1.884e+05  4.093e+05  -0.460 0.645299    
## Store39:Unemployment        1.760e+05  1.157e+05   1.521 0.128297    
## Store40:Unemployment       -2.710e+05  4.093e+05  -0.662 0.508031    
## Store41:Unemployment        3.962e+04  2.121e+05   0.187 0.851848    
## Store42:Unemployment       -2.407e+05  4.134e+05  -0.582 0.560405    
## Store43:Unemployment       -1.222e+05  1.020e+05  -1.199 0.230777    
## Store44:Unemployment       -2.430e+05  4.136e+05  -0.588 0.556872    
## Store45:Unemployment        1.492e+04  2.279e+05   0.065 0.947814    
## Holiday_Flag1:Temperature   1.381e+03  5.972e+02   2.312 0.020821 *  
## Holiday_Flag1:Fuel_Price   -4.665e+04  4.862e+04  -0.959 0.337439    
## Holiday_Flag1:CPI           6.661e+02  5.718e+03   0.116 0.907270    
## Holiday_Flag1:Unemployment -6.261e+04  2.174e+04  -2.879 0.004007 ** 
## Temperature:Fuel_Price      2.234e+03  6.996e+02   3.193 0.001419 ** 
## Temperature:CPI            -3.136e+02  9.376e+01  -3.344 0.000833 ***
## Temperature:Unemployment   -6.836e+02  3.733e+02  -1.831 0.067137 .  
## Fuel_Price:CPI             -1.328e+04  3.981e+03  -3.336 0.000857 ***
## Fuel_Price:Unemployment    -1.002e+04  2.311e+04  -0.434 0.664636    
## CPI:Unemployment           -1.656e+03  4.359e+03  -0.380 0.704049    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 154000 on 4238 degrees of freedom
## Multiple R-squared:  0.9304, Adjusted R-squared:  0.9258 
## F-statistic: 202.9 on 279 and 4238 DF,  p-value: < 2.2e-16
## Backward Elimination Method 
## ---------------------------
## 
## Candidate Terms: 
## 
## 1. Store 
## 2. Holiday_Flag 
## 3. Temperature 
## 4. Fuel_Price 
## 5. CPI 
## 6. Unemployment 
## 7. Store:Holiday_Flag 
## 8. Store:Temperature 
## 9. Store:Fuel_Price 
## 10. Store:CPI 
## 11. Store:Unemployment 
## 12. Holiday_Flag:Temperature 
## 13. Holiday_Flag:Fuel_Price 
## 14. Holiday_Flag:CPI 
## 15. Holiday_Flag:Unemployment 
## 16. Temperature:Fuel_Price 
## 17. Temperature:CPI 
## 18. Temperature:Unemployment 
## 19. Fuel_Price:CPI 
## 20. Fuel_Price:Unemployment 
## 21. CPI:Unemployment 
## 
## 
## Step   => 0 
## Model  => Weekly_Sales ~ Store + Holiday_Flag + Temperature + Fuel_Price + CPI + Unemployment + Store:Holiday_Flag + Store:Temperature + Store:Fuel_Price + Store:CPI + Store:Unemployment + Holiday_Flag:Temperature + Holiday_Flag:Fuel_Price + Holiday_Flag:CPI + Holiday_Flag:Unemployment + Temperature:Fuel_Price + Temperature:CPI + Temperature:Unemployment + Fuel_Price:CPI + Fuel_Price:Unemployment + CPI:Unemployment 
## R2     => 0.93 
## 
## Initiating stepwise selection... 
## 
## Step     => 1 
## Removed  => Holiday_Flag:CPI 
## Model    => Weekly_Sales ~ Store + Holiday_Flag + Temperature + Fuel_Price + CPI + Unemployment + Store:Holiday_Flag + Store:Temperature + Store:Fuel_Price + Store:CPI + Store:Unemployment + Holiday_Flag:Temperature + Holiday_Flag:Fuel_Price + Holiday_Flag:Unemployment + Temperature:Fuel_Price + Temperature:CPI + Temperature:Unemployment + Fuel_Price:CPI + Fuel_Price:Unemployment + CPI:Unemployment 
## R2       => 0.93036 
## 
## Step     => 2 
## Removed  => Unemployment 
## Model    => Weekly_Sales ~ Store + Holiday_Flag + Temperature + Fuel_Price + CPI + Store:Holiday_Flag + Store:Temperature + Store:Fuel_Price + Store:CPI + Store:Unemployment + Holiday_Flag:Temperature + Holiday_Flag:Fuel_Price + Holiday_Flag:Unemployment + Temperature:Fuel_Price + Temperature:CPI + Temperature:Unemployment + Fuel_Price:CPI + Fuel_Price:Unemployment + CPI:Unemployment 
## R2       => 0.93036 
## 
## Step     => 3 
## Removed  => CPI:Unemployment 
## Model    => Weekly_Sales ~ Store + Holiday_Flag + Temperature + Fuel_Price + CPI + Store:Holiday_Flag + Store:Temperature + Store:Fuel_Price + Store:CPI + Store:Unemployment + Holiday_Flag:Temperature + Holiday_Flag:Fuel_Price + Holiday_Flag:Unemployment + Temperature:Fuel_Price + Temperature:CPI + Temperature:Unemployment + Fuel_Price:CPI + Fuel_Price:Unemployment 
## R2       => 0.93036 
## 
## Step     => 4 
## Removed  => Fuel_Price:Unemployment 
## Model    => Weekly_Sales ~ Store + Holiday_Flag + Temperature + Fuel_Price + CPI + Store:Holiday_Flag + Store:Temperature + Store:Fuel_Price + Store:CPI + Store:Unemployment + Holiday_Flag:Temperature + Holiday_Flag:Fuel_Price + Holiday_Flag:Unemployment + Temperature:Fuel_Price + Temperature:CPI + Temperature:Unemployment + Fuel_Price:CPI 
## R2       => 0.93035 
## 
## Step     => 5 
## Removed  => Store:Holiday_Flag 
## Model    => Weekly_Sales ~ Store + Holiday_Flag + Temperature + Fuel_Price + CPI + Store:Temperature + Store:Fuel_Price + Store:CPI + Store:Unemployment + Holiday_Flag:Temperature + Holiday_Flag:Fuel_Price + Holiday_Flag:Unemployment + Temperature:Fuel_Price + Temperature:CPI + Temperature:Unemployment + Fuel_Price:CPI 
## R2       => 0.92961 
## 
## Step     => 6 
## Removed  => Holiday_Flag:Temperature 
## Model    => Weekly_Sales ~ Store + Holiday_Flag + Temperature + Fuel_Price + CPI + Store:Temperature + Store:Fuel_Price + Store:CPI + Store:Unemployment + Holiday_Flag:Fuel_Price + Holiday_Flag:Unemployment + Temperature:Fuel_Price + Temperature:CPI + Temperature:Unemployment + Fuel_Price:CPI 
## R2       => 0.9296 
## 
## Step     => 7 
## Removed  => Holiday_Flag:Unemployment 
## Model    => Weekly_Sales ~ Store + Holiday_Flag + Temperature + Fuel_Price + CPI + Store:Temperature + Store:Fuel_Price + Store:CPI + Store:Unemployment + Holiday_Flag:Fuel_Price + Temperature:Fuel_Price + Temperature:CPI + Temperature:Unemployment + Fuel_Price:CPI 
## R2       => 0.92959 
## 
## 
## No more variables to be removed.
## 
## Variables Removed: 
## 
## => Holiday_Flag:CPI 
## => Unemployment 
## => CPI:Unemployment 
## => Fuel_Price:Unemployment 
## => Store:Holiday_Flag 
## => Holiday_Flag:Temperature 
## => Holiday_Flag:Unemployment
## 
## Call:
## lm(formula = paste(response, "~", paste(c(include, cterms), collapse = " + ")), 
##     data = l)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -615719  -59058   -9155   33518 1674732 
## 
## Coefficients:
##                            Estimate Std. Error t value Pr(>|t|)    
## (Intercept)              -1.277e+07  3.137e+06  -4.071 4.77e-05 ***
## Store2                    4.203e+06  5.658e+06   0.743 0.457586    
## Store3                    2.803e+06  3.857e+06   0.727 0.467536    
## Store4                    5.929e+05  6.196e+06   0.096 0.923772    
## Store5                    1.097e+06  3.746e+06   0.293 0.769596    
## Store6                   -1.135e+07  4.112e+06  -2.759 0.005816 ** 
## Store7                   -7.360e+06  4.566e+06  -1.612 0.107079    
## Store8                    3.934e+05  3.568e+06   0.110 0.912217    
## Store9                    1.491e+06  4.140e+06   0.360 0.718759    
## Store10                   1.121e+07  6.153e+06   1.821 0.068610 .  
## Store11                  -2.594e+06  3.884e+06  -0.668 0.504352    
## Store12                   5.488e+06  5.018e+06   1.094 0.274188    
## Store13                   1.806e+07  8.208e+06   2.200 0.027835 *  
## Store14                   9.815e+06  3.009e+06   3.262 0.001116 ** 
## Store15                   7.643e+06  2.668e+06   2.864 0.004199 ** 
## Store16                   2.956e+06  4.178e+06   0.708 0.479176    
## Store17                   7.823e+06  3.941e+06   1.985 0.047188 *  
## Store18                   1.298e+07  4.595e+06   2.824 0.004764 ** 
## Store19                   5.225e+06  2.689e+06   1.943 0.052044 .  
## Store20                   4.746e+06  2.731e+06   1.738 0.082365 .  
## Store21                  -3.896e+06  4.880e+06  -0.798 0.424637    
## Store22                   3.375e+06  4.327e+06   0.780 0.435426    
## Store23                   6.687e+06  5.097e+06   1.312 0.189608    
## Store24                   3.795e+06  2.959e+06   1.282 0.199835    
## Store25                   1.449e+06  2.690e+06   0.538 0.590293    
## Store26                   3.642e+06  5.849e+06   0.623 0.533470    
## Store27                   8.426e+06  2.650e+06   3.180 0.001483 ** 
## Store28                   5.842e+06  4.725e+06   1.236 0.216354    
## Store29                   4.123e+06  4.195e+06   0.983 0.325735    
## Store30                   5.491e+06  5.461e+06   1.006 0.314675    
## Store31                  -7.471e+06  5.453e+06  -1.370 0.170741    
## Store32                  -6.955e+06  4.473e+06  -1.555 0.120054    
## Store33                   6.588e+06  6.482e+06   1.016 0.309514    
## Store34                   2.256e+06  3.728e+06   0.605 0.545107    
## Store35                   7.541e+06  2.779e+06   2.714 0.006680 ** 
## Store36                   7.611e+06  5.431e+06   1.401 0.161156    
## Store37                   4.588e+06  5.068e+06   0.905 0.365430    
## Store38                   6.907e+06  5.357e+06   1.289 0.197296    
## Store39                  -1.295e+07  4.832e+06  -2.681 0.007368 ** 
## Store40                   7.306e+06  5.095e+06   1.434 0.151625    
## Store41                  -2.652e+06  5.355e+06  -0.495 0.620409    
## Store42                   9.420e+06  6.442e+06   1.462 0.143767    
## Store43                   4.522e+06  2.931e+06   1.543 0.122958    
## Store44                   1.071e+07  9.309e+06   1.150 0.250157    
## Store45                   2.392e+06  2.911e+06   0.822 0.411270    
## Holiday_Flag1            -1.126e+05  7.170e+04  -1.571 0.116285    
## Temperature               5.884e+04  1.962e+04   2.999 0.002728 ** 
## Fuel_Price                2.027e+06  6.696e+05   3.028 0.002477 ** 
## CPI                       6.774e+04  1.381e+04   4.906 9.65e-07 ***
## Store2:Temperature       -6.368e+02  1.550e+03  -0.411 0.681300    
## Store3:Temperature        1.865e+03  1.785e+03   1.045 0.296199    
## Store4:Temperature       -2.944e+04  8.308e+03  -3.544 0.000399 ***
## Store5:Temperature        1.686e+03  1.715e+03   0.983 0.325483    
## Store6:Temperature        1.938e+03  1.652e+03   1.173 0.240748    
## Store7:Temperature       -2.616e+03  2.475e+03  -1.057 0.290484    
## Store8:Temperature        8.720e+02  1.665e+03   0.524 0.600424    
## Store9:Temperature        1.919e+03  1.669e+03   1.150 0.250246    
## Store10:Temperature      -3.280e+04  8.138e+03  -4.030 5.67e-05 ***
## Store11:Temperature      -5.356e+02  1.767e+03  -0.303 0.761869    
## Store12:Temperature      -2.460e+04  7.746e+03  -3.175 0.001507 ** 
## Store13:Temperature      -2.710e+04  8.201e+03  -3.305 0.000958 ***
## Store14:Temperature      -9.899e+03  3.133e+03  -3.159 0.001592 ** 
## Store15:Temperature      -2.216e+04  7.610e+03  -2.912 0.003609 ** 
## Store16:Temperature      -3.038e+03  2.660e+03  -1.142 0.253557    
## Store17:Temperature      -2.409e+04  8.242e+03  -2.923 0.003482 ** 
## Store18:Temperature      -1.978e+04  7.476e+03  -2.645 0.008187 ** 
## Store19:Temperature      -2.156e+04  7.608e+03  -2.833 0.004628 ** 
## Store20:Temperature      -5.401e+03  1.658e+03  -3.258 0.001131 ** 
## Store21:Temperature       1.453e+03  1.576e+03   0.922 0.356699    
## Store22:Temperature      -2.097e+04  7.193e+03  -2.915 0.003573 ** 
## Store23:Temperature      -2.385e+04  7.966e+03  -2.994 0.002773 ** 
## Store24:Temperature      -2.024e+04  7.527e+03  -2.690 0.007182 ** 
## Store25:Temperature       9.776e+02  1.660e+03   0.589 0.556047    
## Store26:Temperature      -2.048e+04  7.600e+03  -2.695 0.007069 ** 
## Store27:Temperature      -1.774e+04  7.237e+03  -2.452 0.014260 *  
## Store28:Temperature      -2.375e+04  7.726e+03  -3.074 0.002125 ** 
## Store29:Temperature      -2.202e+04  7.366e+03  -2.989 0.002814 ** 
## Store30:Temperature       2.172e+03  1.580e+03   1.375 0.169277    
## Store31:Temperature       1.501e+03  1.558e+03   0.964 0.335305    
## Store32:Temperature      -4.047e+03  2.398e+03  -1.688 0.091578 .  
## Store33:Temperature      -2.362e+04  8.100e+03  -2.916 0.003562 ** 
## Store34:Temperature      -2.369e+04  7.774e+03  -3.047 0.002327 ** 
## Store35:Temperature      -1.777e+04  7.106e+03  -2.500 0.012439 *  
## Store36:Temperature       2.846e+03  1.827e+03   1.558 0.119311    
## Store37:Temperature       1.570e+03  1.862e+03   0.843 0.399067    
## Store38:Temperature      -2.140e+04  7.736e+03  -2.767 0.005688 ** 
## Store39:Temperature       3.876e+03  1.722e+03   2.250 0.024472 *  
## Store40:Temperature      -2.264e+04  7.969e+03  -2.841 0.004525 ** 
## Store41:Temperature      -2.794e+03  2.559e+03  -1.092 0.274931    
## Store42:Temperature      -2.410e+04  8.126e+03  -2.965 0.003040 ** 
## Store43:Temperature       1.802e+03  1.842e+03   0.978 0.328039    
## Store44:Temperature      -2.410e+04  8.264e+03  -2.917 0.003556 ** 
## Store45:Temperature      -8.399e+03  3.113e+03  -2.698 0.007010 ** 
## Store2:Fuel_Price        -1.216e+05  9.670e+04  -1.258 0.208552    
## Store3:Fuel_Price         8.158e+04  1.055e+05   0.774 0.439214    
## Store4:Fuel_Price        -9.807e+05  2.847e+05  -3.445 0.000577 ***
## Store5:Fuel_Price         1.094e+04  9.043e+04   0.121 0.903686    
## Store6:Fuel_Price        -1.481e+05  8.738e+04  -1.695 0.090165 .  
## Store7:Fuel_Price        -1.963e+05  1.140e+05  -1.722 0.085076 .  
## Store8:Fuel_Price         3.536e+04  9.228e+04   0.383 0.701634    
## Store9:Fuel_Price         6.690e+04  9.447e+04   0.708 0.478872    
## Store10:Fuel_Price       -9.529e+05  2.844e+05  -3.350 0.000815 ***
## Store11:Fuel_Price       -6.592e+04  1.055e+05  -0.625 0.531963    
## Store12:Fuel_Price       -8.780e+05  2.851e+05  -3.080 0.002086 ** 
## Store13:Fuel_Price       -7.723e+05  2.931e+05  -2.635 0.008444 ** 
## Store14:Fuel_Price       -3.100e+05  1.286e+05  -2.410 0.015996 *  
## Store15:Fuel_Price       -6.977e+05  2.702e+05  -2.582 0.009852 ** 
## Store16:Fuel_Price       -2.506e+05  1.245e+05  -2.013 0.044199 *  
## Store17:Fuel_Price       -7.445e+05  2.894e+05  -2.573 0.010127 *  
## Store18:Fuel_Price       -8.827e+05  2.666e+05  -3.311 0.000939 ***
## Store19:Fuel_Price       -9.909e+05  2.681e+05  -3.696 0.000222 ***
## Store20:Fuel_Price       -1.600e+05  8.976e+04  -1.782 0.074764 .  
## Store21:Fuel_Price       -5.369e+04  9.099e+04  -0.590 0.555188    
## Store22:Fuel_Price       -7.714e+05  2.547e+05  -3.029 0.002470 ** 
## Store23:Fuel_Price       -9.052e+05  2.644e+05  -3.424 0.000623 ***
## Store24:Fuel_Price       -9.064e+05  2.657e+05  -3.411 0.000653 ***
## Store25:Fuel_Price       -1.068e+05  9.261e+04  -1.153 0.249002    
## Store26:Fuel_Price       -7.872e+05  2.682e+05  -2.935 0.003354 ** 
## Store27:Fuel_Price       -8.655e+05  2.558e+05  -3.383 0.000723 ***
## Store28:Fuel_Price       -9.318e+05  2.854e+05  -3.265 0.001105 ** 
## Store29:Fuel_Price       -8.041e+05  2.666e+05  -3.017 0.002570 ** 
## Store30:Fuel_Price        2.301e+04  9.201e+04   0.250 0.802516    
## Store31:Fuel_Price       -6.409e+04  9.388e+04  -0.683 0.494881    
## Store32:Fuel_Price       -1.672e+05  1.110e+05  -1.506 0.132167    
## Store33:Fuel_Price       -8.545e+05  2.850e+05  -2.999 0.002728 ** 
## Store34:Fuel_Price       -9.770e+05  2.891e+05  -3.379 0.000733 ***
## Store35:Fuel_Price       -7.140e+05  2.574e+05  -2.774 0.005558 ** 
## Store36:Fuel_Price        1.752e+04  9.708e+04   0.180 0.856834    
## Store37:Fuel_Price        4.617e+04  1.004e+05   0.460 0.645580    
## Store38:Fuel_Price       -8.171e+05  2.874e+05  -2.843 0.004492 ** 
## Store39:Fuel_Price       -1.640e+05  9.504e+04  -1.725 0.084538 .  
## Store40:Fuel_Price       -8.449e+05  2.649e+05  -3.190 0.001435 ** 
## Store41:Fuel_Price       -1.189e+05  1.133e+05  -1.049 0.294335    
## Store42:Fuel_Price       -8.359e+05  2.860e+05  -2.923 0.003487 ** 
## Store43:Fuel_Price       -1.918e+04  1.053e+05  -0.182 0.855379    
## Store44:Fuel_Price       -7.895e+05  2.995e+05  -2.636 0.008428 ** 
## Store45:Fuel_Price       -2.798e+05  1.288e+05  -2.172 0.029890 *  
## Store2:CPI               -1.335e+04  2.244e+04  -0.595 0.551895    
## Store3:CPI               -1.663e+04  1.526e+04  -1.090 0.275811    
## Store4:CPI                5.254e+04  4.397e+04   1.195 0.232167    
## Store5:CPI               -1.000e+04  1.462e+04  -0.684 0.493763    
## Store6:CPI                4.451e+04  1.623e+04   2.743 0.006112 ** 
## Store7:CPI                2.930e+04  1.805e+04   1.623 0.104608    
## Store8:CPI               -5.244e+03  1.386e+04  -0.378 0.705251    
## Store9:CPI               -1.163e+04  1.645e+04  -0.707 0.479638    
## Store10:CPI              -2.781e+04  4.235e+04  -0.657 0.511423    
## Store11:CPI               1.002e+04  1.543e+04   0.649 0.516067    
## Store12:CPI              -9.234e+02  3.475e+04  -0.027 0.978799    
## Store13:CPI              -8.299e+04  5.838e+04  -1.422 0.155188    
## Store14:CPI              -4.113e+04  1.127e+04  -3.648 0.000267 ***
## Store15:CPI              -3.647e+04  1.775e+04  -2.055 0.039962 *  
## Store16:CPI              -1.064e+04  1.595e+04  -0.667 0.504553    
## Store17:CPI              -2.053e+04  2.500e+04  -0.821 0.411713    
## Store18:CPI              -4.506e+04  2.601e+04  -1.732 0.083328 .  
## Store19:CPI               1.363e+04  1.765e+04   0.772 0.439885    
## Store20:CPI              -8.889e+03  1.068e+04  -0.832 0.405212    
## Store21:CPI               1.024e+04  1.931e+04   0.530 0.596107    
## Store22:CPI               2.789e+03  2.385e+04   0.117 0.906915    
## Store23:CPI              -3.701e+03  3.080e+04  -0.120 0.904372    
## Store24:CPI               2.045e+04  2.313e+04   0.884 0.376623    
## Store25:CPI              -7.277e+03  1.073e+04  -0.678 0.497658    
## Store26:CPI               4.147e+03  3.085e+04   0.134 0.893089    
## Store27:CPI              -1.637e+04  1.780e+04  -0.920 0.357672    
## Store28:CPI              -1.187e+03  3.249e+04  -0.037 0.970853    
## Store29:CPI              -1.600e+03  2.408e+04  -0.066 0.947017    
## Store30:CPI              -2.719e+04  2.150e+04  -1.264 0.206238    
## Store31:CPI               2.811e+04  2.156e+04   1.304 0.192364    
## Store32:CPI               2.871e+04  1.783e+04   1.610 0.107472    
## Store33:CPI              -1.647e+04  4.522e+04  -0.364 0.715776    
## Store34:CPI               2.387e+04  2.414e+04   0.989 0.322677    
## Store35:CPI              -5.317e+04  1.648e+04  -3.226 0.001266 ** 
## Store36:CPI              -3.820e+04  2.202e+04  -1.734 0.082912 .  
## Store37:CPI              -2.372e+04  2.064e+04  -1.149 0.250624    
## Store38:CPI              -1.718e+04  3.753e+04  -0.458 0.647098    
## Store39:CPI               5.489e+04  1.950e+04   2.815 0.004907 ** 
## Store40:CPI              -1.355e+04  3.077e+04  -0.440 0.659677    
## Store41:CPI               1.445e+04  2.116e+04   0.683 0.494646    
## Store42:CPI              -3.242e+04  4.454e+04  -0.728 0.466699    
## Store43:CPI              -2.174e+04  1.204e+04  -1.805 0.071105 .  
## Store44:CPI              -4.562e+04  6.731e+04  -0.678 0.497964    
## Store45:CPI              -9.723e+03  1.115e+04  -0.872 0.383347    
## Store1:Unemployment       7.025e+04  7.515e+04   0.935 0.349930    
## Store2:Unemployment       2.374e+03  1.259e+05   0.019 0.984961    
## Store3:Unemployment      -3.043e+04  9.617e+04  -0.316 0.751704    
## Store4:Unemployment       2.042e+03  4.926e+04   0.041 0.966940    
## Store5:Unemployment       2.512e+04  1.082e+05   0.232 0.816380    
## Store6:Unemployment       3.762e+05  1.010e+05   3.725 0.000198 ***
## Store7:Unemployment       2.829e+05  1.224e+05   2.310 0.020915 *  
## Store8:Unemployment       5.781e+04  1.074e+05   0.538 0.590421    
## Store9:Unemployment       2.159e+04  1.072e+05   0.201 0.840359    
## Store10:Unemployment     -1.402e+04  7.372e+04  -0.190 0.849205    
## Store11:Unemployment      1.302e+05  9.633e+04   1.352 0.176427    
## Store12:Unemployment      4.343e+04  4.395e+04   0.988 0.323106    
## Store13:Unemployment     -1.301e+05  9.566e+04  -1.360 0.173821    
## Store14:Unemployment      1.111e+05  1.710e+05   0.650 0.515797    
## Store15:Unemployment      2.200e+05  1.289e+05   1.707 0.087839 .  
## Store16:Unemployment     -1.097e+04  1.623e+05  -0.068 0.946140    
## Store17:Unemployment     -1.496e+04  7.574e+04  -0.198 0.843433    
## Store18:Unemployment     -1.623e+05  1.086e+05  -1.494 0.135269    
## Store19:Unemployment     -9.431e+04  1.227e+05  -0.769 0.442069    
## Store20:Unemployment     -1.146e+05  8.543e+04  -1.342 0.179716    
## Store21:Unemployment      1.977e+05  1.067e+05   1.853 0.063969 .  
## Store22:Unemployment      1.547e+05  1.083e+05   1.429 0.153102    
## Store23:Unemployment     -4.589e+04  1.351e+05  -0.340 0.734125    
## Store24:Unemployment     -8.271e+04  1.248e+05  -0.663 0.507528    
## Store25:Unemployment      2.054e+04  7.663e+04   0.268 0.788677    
## Store26:Unemployment      1.136e+05  1.915e+05   0.593 0.553035    
## Store27:Unemployment     -2.867e+04  1.277e+05  -0.224 0.822382    
## Store28:Unemployment      5.270e+04  4.137e+04   1.274 0.202739    
## Store29:Unemployment      9.266e+04  7.836e+04   1.183 0.237028    
## Store30:Unemployment     -5.558e+04  1.236e+05  -0.450 0.652999    
## Store31:Unemployment      2.479e+05  1.223e+05   2.028 0.042648 *  
## Store32:Unemployment      3.148e+05  1.139e+05   2.765 0.005725 ** 
## Store33:Unemployment      4.501e+04  7.065e+04   0.637 0.524159    
## Store34:Unemployment      6.776e+04  4.691e+04   1.445 0.148654    
## Store35:Unemployment      4.998e+05  1.125e+05   4.444 9.06e-06 ***
## Store36:Unemployment     -3.494e+04  1.060e+05  -0.330 0.741684    
## Store37:Unemployment     -2.768e+04  9.763e+04  -0.283 0.776810    
## Store38:Unemployment      1.309e+04  4.586e+04   0.285 0.775324    
## Store39:Unemployment      2.387e+05  9.628e+04   2.480 0.013188 *  
## Store40:Unemployment     -4.474e+04  1.339e+05  -0.334 0.738357    
## Store41:Unemployment      1.407e+05  1.705e+05   0.825 0.409329    
## Store42:Unemployment     -1.643e+04  7.814e+04  -0.210 0.833469    
## Store43:Unemployment     -2.495e+04  5.679e+04  -0.439 0.660478    
## Store44:Unemployment     -2.832e+04  1.030e+05  -0.275 0.783475    
## Store45:Unemployment      1.276e+05  1.588e+05   0.803 0.421947    
## Holiday_Flag1:Fuel_Price  5.219e+04  2.183e+04   2.391 0.016867 *  
## Temperature:Fuel_Price    2.333e+03  6.910e+02   3.376 0.000742 ***
## Temperature:CPI          -2.996e+02  9.086e+01  -3.297 0.000986 ***
## Temperature:Unemployment -5.607e+02  3.649e+02  -1.537 0.124454    
## Fuel_Price:CPI           -1.033e+04  3.082e+03  -3.352 0.000810 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 153900 on 4287 degrees of freedom
## Multiple R-squared:  0.9296, Adjusted R-squared:  0.9258 
## F-statistic: 246.1 on 230 and 4287 DF,  p-value: < 2.2e-16

6. Scoring with validation set

7. Calculating R^2

Conclusion: This model, using the training data, has an R^2 of 0.934. The model, using the validation data, has an R^2 of 0.912

Interpret 3 predictors

Fuel Price: When fuel prices go up, sales go down

Holiday_Flag1: Sales increase during holidays

CPI: As the CPI goes up, so do sales