1. Prepare your data for modeling

##      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
##      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.   :0.0001505  
##  1st Qu.:0.2459924  
##  Median :0.4942164  
##  Mean   :0.4970587  
##  3rd Qu.:0.7476742  
##  Max.   :0.9998803  
## 
## 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] 0.0765 0.5713 0.3018 0.2427 0.5339 ...

##      Min.   1st Qu.    Median      Mean   3rd Qu.      Max. 
## 0.0001505 0.2459924 0.4942164 0.4970587 0.7476742 0.9998803

2. Develop a linear model to predict sales

## 
## Call:
## lm(formula = Weekly_Sales ~ . - Date, data = trainlm)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -538619  -69911  -11523   40306 1831752 
## 
## Coefficients:
##                 Estimate Std. Error t value Pr(>|t|)    
## (Intercept)    1277290.0   270928.5   4.714 2.50e-06 ***
## Store2          376185.6    22815.3  16.488  < 2e-16 ***
## Store3        -1177935.8    23612.2 -49.887  < 2e-16 ***
## Store4          752470.7   113219.6   6.646 3.37e-11 ***
## Store5        -1279970.8    23567.4 -54.311  < 2e-16 ***
## Store6          -12620.1    23289.8  -0.542  0.58793    
## Store7         -923524.1    34275.8 -26.944  < 2e-16 ***
## Store8         -707956.0    23767.4 -29.787  < 2e-16 ***
## Store9        -1066350.4    24551.3 -43.433  < 2e-16 ***
## Store10         658995.0   110067.2   5.987 2.30e-09 ***
## Store11        -228922.0    22740.7 -10.067  < 2e-16 ***
## Store12        -130590.0   103479.0  -1.262  0.20702    
## Store13         685363.7   111335.7   6.156 8.12e-10 ***
## Store14         567314.4    42175.9  13.451  < 2e-16 ***
## Store15        -676414.7   103202.8  -6.554 6.22e-11 ***
## Store16       -1015079.2    37890.5 -26.790  < 2e-16 ***
## Store17        -441065.9   112652.7  -3.915 9.16e-05 ***
## Store18        -199640.4   100798.8  -1.981  0.04770 *  
## Store19         126915.3   102860.9   1.234  0.21732    
## Store20         543513.8    24590.6  22.103  < 2e-16 ***
## Store21        -811479.9    22931.6 -35.387  < 2e-16 ***
## Store22        -282146.8    97540.3  -2.893  0.00384 ** 
## Store23          -9253.3   109856.4  -0.084  0.93288    
## Store24          68029.0   102261.6   0.665  0.50593    
## Store25        -840890.0    24662.3 -34.096  < 2e-16 ***
## Store26        -310573.0   102879.6  -3.019  0.00255 ** 
## Store27         488218.3    98293.7   4.967 7.05e-07 ***
## Store28         179423.4   103492.0   1.734  0.08304 .  
## Store29        -718529.7    99164.2  -7.246 5.03e-13 ***
## Store30       -1121671.6    23109.7 -48.537  < 2e-16 ***
## Store31        -166114.4    22755.5  -7.300 3.38e-13 ***
## Store32        -307709.5    34086.5  -9.027  < 2e-16 ***
## Store33        -987021.2   109690.9  -8.998  < 2e-16 ***
## Store34        -285177.6   105176.9  -2.711  0.00673 ** 
## Store35        -377848.3    95884.3  -3.941 8.25e-05 ***
## Store36       -1177306.2    22336.6 -52.708  < 2e-16 ***
## Store37       -1032873.2    22950.4 -45.004  < 2e-16 ***
## Store38        -760356.8   103568.9  -7.342 2.49e-13 ***
## Store39        -112744.5    23462.5  -4.805 1.60e-06 ***
## Store40        -435204.7   109768.8  -3.965 7.46e-05 ***
## Store41        -248479.7    36882.3  -6.737 1.82e-11 ***
## Store42        -700178.0   110147.3  -6.357 2.26e-10 ***
## Store43        -849948.6    25597.6 -33.204  < 2e-16 ***
## Store44       -1018652.5   112030.3  -9.093  < 2e-16 ***
## Store45        -660285.7    42160.5 -15.661  < 2e-16 ***
## Holiday_Flag1    78741.6     9571.4   8.227 2.49e-16 ***
## Temperature       -681.3      156.7  -4.348 1.41e-05 ***
## Fuel_Price      -48630.5     8587.2  -5.663 1.58e-08 ***
## CPI               3072.2     1234.0   2.490  0.01282 *  
## Unemployment    -23643.2     5080.7  -4.654 3.36e-06 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 160000 on 4507 degrees of freedom
## Multiple R-squared:  0.9204, Adjusted R-squared:  0.9195 
## F-statistic:  1063 on 49 and 4507 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 
## 
## 
## Step   => 0 
## Model  => Weekly_Sales ~ Store + Holiday_Flag + Temperature + Fuel_Price + CPI + Unemployment 
## R2     => 0.92 
## 
## 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 
## -538619  -69911  -11523   40306 1831752 
## 
## Coefficients:
##                 Estimate Std. Error t value Pr(>|t|)    
## (Intercept)    1277290.0   270928.5   4.714 2.50e-06 ***
## Store2          376185.6    22815.3  16.488  < 2e-16 ***
## Store3        -1177935.8    23612.2 -49.887  < 2e-16 ***
## Store4          752470.7   113219.6   6.646 3.37e-11 ***
## Store5        -1279970.8    23567.4 -54.311  < 2e-16 ***
## Store6          -12620.1    23289.8  -0.542  0.58793    
## Store7         -923524.1    34275.8 -26.944  < 2e-16 ***
## Store8         -707956.0    23767.4 -29.787  < 2e-16 ***
## Store9        -1066350.4    24551.3 -43.433  < 2e-16 ***
## Store10         658995.0   110067.2   5.987 2.30e-09 ***
## Store11        -228922.0    22740.7 -10.067  < 2e-16 ***
## Store12        -130590.0   103479.0  -1.262  0.20702    
## Store13         685363.7   111335.7   6.156 8.12e-10 ***
## Store14         567314.4    42175.9  13.451  < 2e-16 ***
## Store15        -676414.7   103202.8  -6.554 6.22e-11 ***
## Store16       -1015079.2    37890.5 -26.790  < 2e-16 ***
## Store17        -441065.9   112652.7  -3.915 9.16e-05 ***
## Store18        -199640.4   100798.8  -1.981  0.04770 *  
## Store19         126915.3   102860.9   1.234  0.21732    
## Store20         543513.8    24590.6  22.103  < 2e-16 ***
## Store21        -811479.9    22931.6 -35.387  < 2e-16 ***
## Store22        -282146.8    97540.3  -2.893  0.00384 ** 
## Store23          -9253.3   109856.4  -0.084  0.93288    
## Store24          68029.0   102261.6   0.665  0.50593    
## Store25        -840890.0    24662.3 -34.096  < 2e-16 ***
## Store26        -310573.0   102879.6  -3.019  0.00255 ** 
## Store27         488218.3    98293.7   4.967 7.05e-07 ***
## Store28         179423.4   103492.0   1.734  0.08304 .  
## Store29        -718529.7    99164.2  -7.246 5.03e-13 ***
## Store30       -1121671.6    23109.7 -48.537  < 2e-16 ***
## Store31        -166114.4    22755.5  -7.300 3.38e-13 ***
## Store32        -307709.5    34086.5  -9.027  < 2e-16 ***
## Store33        -987021.2   109690.9  -8.998  < 2e-16 ***
## Store34        -285177.6   105176.9  -2.711  0.00673 ** 
## Store35        -377848.3    95884.3  -3.941 8.25e-05 ***
## Store36       -1177306.2    22336.6 -52.708  < 2e-16 ***
## Store37       -1032873.2    22950.4 -45.004  < 2e-16 ***
## Store38        -760356.8   103568.9  -7.342 2.49e-13 ***
## Store39        -112744.5    23462.5  -4.805 1.60e-06 ***
## Store40        -435204.7   109768.8  -3.965 7.46e-05 ***
## Store41        -248479.7    36882.3  -6.737 1.82e-11 ***
## Store42        -700178.0   110147.3  -6.357 2.26e-10 ***
## Store43        -849948.6    25597.6 -33.204  < 2e-16 ***
## Store44       -1018652.5   112030.3  -9.093  < 2e-16 ***
## Store45        -660285.7    42160.5 -15.661  < 2e-16 ***
## Holiday_Flag1    78741.6     9571.4   8.227 2.49e-16 ***
## Temperature       -681.3      156.7  -4.348 1.41e-05 ***
## Fuel_Price      -48630.5     8587.2  -5.663 1.58e-08 ***
## CPI               3072.2     1234.0   2.490  0.01282 *  
## Unemployment    -23643.2     5080.7  -4.654 3.36e-06 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 160000 on 4507 degrees of freedom
## Multiple R-squared:  0.9204, Adjusted R-squared:  0.9195 
## F-statistic:  1063 on 49 and 4507 DF,  p-value: < 2.2e-16
## 
## Call:
## lm(formula = Weekly_Sales ~ (. - Date)^2, data = trainlm)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -682241  -54563   -9320   31979 1661245 
## 
## Coefficients:
##                              Estimate Std. Error t value Pr(>|t|)    
## (Intercept)                -2.176e+07  8.030e+06  -2.709 0.006768 ** 
## Store2                     -2.238e+06  5.158e+06  -0.434 0.664391    
## Store3                      5.106e+06  4.011e+06   1.273 0.203114    
## Store4                      5.807e+06  7.343e+06   0.791 0.429115    
## Store5                      3.935e+06  4.168e+06   0.944 0.345281    
## Store6                     -3.750e+06  4.318e+06  -0.869 0.385164    
## Store7                     -3.481e+06  4.772e+06  -0.730 0.465710    
## Store8                      5.121e+06  3.854e+06   1.329 0.183986    
## Store9                      9.315e+05  4.496e+06   0.207 0.835883    
## Store10                     1.567e+07  6.707e+06   2.336 0.019516 *  
## Store11                    -8.264e+05  3.631e+06  -0.228 0.819966    
## Store12                     7.006e+06  5.083e+06   1.378 0.168183    
## Store13                     1.617e+07  8.845e+06   1.828 0.067597 .  
## Store14                     1.285e+07  3.126e+06   4.111 4.01e-05 ***
## Store15                     1.125e+07  3.965e+06   2.837 0.004578 ** 
## Store16                     3.831e+06  4.708e+06   0.814 0.415776    
## Store17                     1.450e+07  5.434e+06   2.668 0.007658 ** 
## Store18                     1.154e+07  5.271e+06   2.190 0.028575 *  
## Store19                     1.301e+07  3.936e+06   3.305 0.000959 ***
## Store20                     3.354e+06  2.923e+06   1.147 0.251335    
## Store21                    -1.317e+06  5.673e+06  -0.232 0.816422    
## Store22                     6.718e+06  5.158e+06   1.302 0.192838    
## Store23                     1.167e+07  6.920e+06   1.687 0.091748 .  
## Store24                     8.602e+06  4.002e+06   2.149 0.031658 *  
## Store25                     3.694e+06  2.956e+06   1.250 0.211490    
## Store26                     1.024e+07  6.625e+06   1.545 0.122383    
## Store27                     1.301e+07  3.787e+06   3.435 0.000598 ***
## Store28                     8.012e+06  4.900e+06   1.635 0.102122    
## Store29                     8.139e+06  4.658e+06   1.747 0.080646 .  
## Store30                     6.326e+06  5.576e+06   1.135 0.256633    
## Store31                    -3.427e+06  5.128e+06  -0.668 0.504008    
## Store32                    -4.454e+06  4.659e+06  -0.956 0.339106    
## Store33                     1.027e+07  6.564e+06   1.564 0.117908    
## Store34                     1.124e+07  4.272e+06   2.630 0.008561 ** 
## Store35                     9.568e+06  3.569e+06   2.681 0.007371 ** 
## Store36                     8.751e+06  5.097e+06   1.717 0.086106 .  
## Store37                     5.357e+06  4.950e+06   1.082 0.279228    
## Store38                     5.764e+06  5.071e+06   1.137 0.255728    
## Store39                    -1.024e+07  5.674e+06  -1.804 0.071263 .  
## Store40                     1.170e+07  6.995e+06   1.673 0.094389 .  
## Store41                    -8.925e+06  5.812e+06  -1.536 0.124722    
## Store42                     1.381e+07  7.102e+06   1.944 0.051949 .  
## Store43                     5.367e+06  3.398e+06   1.579 0.114314    
## Store44                     1.366e+07  9.230e+06   1.480 0.139019    
## Store45                     3.703e+06  3.019e+06   1.227 0.220060    
## Holiday_Flag1               2.705e+05  1.166e+06   0.232 0.816549    
## Temperature                 6.302e+04  1.959e+04   3.218 0.001303 ** 
## Fuel_Price                  2.562e+06  9.387e+05   2.729 0.006383 ** 
## CPI                         1.069e+05  3.732e+04   2.865 0.004192 ** 
## Unemployment                7.956e+05  8.870e+05   0.897 0.369804    
## Store2:Holiday_Flag1        8.883e+04  8.290e+04   1.072 0.283985    
## Store3:Holiday_Flag1       -7.263e+04  8.340e+04  -0.871 0.383838    
## Store4:Holiday_Flag1        6.961e+04  4.977e+05   0.140 0.888781    
## Store5:Holiday_Flag1       -6.369e+04  8.766e+04  -0.727 0.467512    
## Store6:Holiday_Flag1        1.687e+04  8.701e+04   0.194 0.846281    
## Store7:Holiday_Flag1        8.325e+04  1.422e+05   0.585 0.558387    
## Store8:Holiday_Flag1       -4.697e+04  8.789e+04  -0.534 0.593054    
## Store9:Holiday_Flag1       -4.801e+04  9.331e+04  -0.515 0.606909    
## Store10:Holiday_Flag1       1.012e+05  4.891e+05   0.207 0.836078    
## Store11:Holiday_Flag1      -1.220e+05  8.464e+04  -1.441 0.149705    
## Store12:Holiday_Flag1       1.062e+05  4.683e+05   0.227 0.820537    
## Store13:Holiday_Flag1      -7.326e+04  4.877e+05  -0.150 0.880597    
## Store14:Holiday_Flag1       1.291e+05  1.841e+05   0.702 0.482992    
## Store15:Holiday_Flag1       1.839e+04  4.578e+05   0.040 0.967960    
## Store16:Holiday_Flag1      -9.811e+03  1.534e+05  -0.064 0.949019    
## Store17:Holiday_Flag1      -1.095e+03  4.934e+05  -0.002 0.998230    
## Store18:Holiday_Flag1      -5.685e+04  4.491e+05  -0.127 0.899271    
## Store19:Holiday_Flag1      -2.700e+04  4.578e+05  -0.059 0.952972    
## Store20:Holiday_Flag1       1.205e+05  9.254e+04   1.302 0.192955    
## Store21:Holiday_Flag1      -7.135e+03  7.859e+04  -0.091 0.927660    
## Store22:Holiday_Flag1      -6.371e+04  4.344e+05  -0.147 0.883416    
## Store23:Holiday_Flag1       5.674e+04  4.813e+05   0.118 0.906161    
## Store24:Holiday_Flag1       8.787e+04  4.564e+05   0.193 0.847337    
## Store25:Holiday_Flag1      -6.784e+04  9.641e+04  -0.704 0.481665    
## Store26:Holiday_Flag1       3.240e+04  4.546e+05   0.071 0.943187    
## Store27:Holiday_Flag1       5.021e+03  4.371e+05   0.011 0.990835    
## Store28:Holiday_Flag1       7.459e+04  4.681e+05   0.159 0.873401    
## Store29:Holiday_Flag1       6.354e+03  4.461e+05   0.014 0.988635    
## Store30:Holiday_Flag1      -7.241e+04  9.163e+04  -0.790 0.429406    
## Store31:Holiday_Flag1      -1.204e+04  8.032e+04  -0.150 0.880898    
## Store32:Holiday_Flag1       3.468e+04  1.427e+05   0.243 0.808042    
## Store33:Holiday_Flag1      -1.042e+05  4.850e+05  -0.215 0.829822    
## Store34:Holiday_Flag1       6.938e+04  4.661e+05   0.149 0.881688    
## Store35:Holiday_Flag1       2.171e+05  4.274e+05   0.508 0.611566    
## Store36:Holiday_Flag1      -8.699e+04  8.342e+04  -1.043 0.297104    
## Store37:Holiday_Flag1      -9.670e+04  8.815e+04  -1.097 0.272719    
## Store38:Holiday_Flag1      -5.076e+04  4.711e+05  -0.108 0.914204    
## Store39:Holiday_Flag1       4.988e+04  9.069e+04   0.550 0.582305    
## Store40:Holiday_Flag1      -4.238e+04  4.803e+05  -0.088 0.929680    
## Store41:Holiday_Flag1      -3.551e+04  1.523e+05  -0.233 0.815702    
## Store42:Holiday_Flag1      -1.082e+05  4.896e+05  -0.221 0.825172    
## Store43:Holiday_Flag1      -4.641e+04  9.803e+04  -0.473 0.635958    
## Store44:Holiday_Flag1      -9.148e+04  4.941e+05  -0.185 0.853145    
## Store45:Holiday_Flag1      -8.255e+04  1.887e+05  -0.437 0.661867    
## Store2:Temperature         -1.976e+03  1.580e+03  -1.251 0.210939    
## Store3:Temperature          1.013e+03  1.817e+03   0.558 0.577061    
## Store4:Temperature         -2.915e+04  8.320e+03  -3.504 0.000463 ***
## Store5:Temperature          1.124e+03  1.670e+03   0.673 0.501094    
## Store6:Temperature          1.502e+03  1.645e+03   0.913 0.361249    
## Store7:Temperature         -1.724e+03  2.422e+03  -0.712 0.476685    
## Store8:Temperature         -5.713e+01  1.617e+03  -0.035 0.971817    
## Store9:Temperature          1.378e+03  1.665e+03   0.827 0.408114    
## Store10:Temperature        -3.370e+04  8.153e+03  -4.134 3.63e-05 ***
## Store11:Temperature        -8.676e+02  1.738e+03  -0.499 0.617563    
## Store12:Temperature        -2.362e+04  7.800e+03  -3.029 0.002472 ** 
## Store13:Temperature        -2.670e+04  8.190e+03  -3.260 0.001123 ** 
## Store14:Temperature        -8.356e+03  3.089e+03  -2.705 0.006853 ** 
## Store15:Temperature        -2.313e+04  7.608e+03  -3.040 0.002381 ** 
## Store16:Temperature        -3.703e+03  2.601e+03  -1.424 0.154522    
## Store17:Temperature        -2.469e+04  8.240e+03  -2.997 0.002743 ** 
## Store18:Temperature        -2.185e+04  7.483e+03  -2.919 0.003528 ** 
## Store19:Temperature        -2.267e+04  7.588e+03  -2.988 0.002826 ** 
## Store20:Temperature        -2.150e+03  1.651e+03  -1.302 0.192945    
## Store21:Temperature         1.597e+03  1.596e+03   1.000 0.317156    
## Store22:Temperature        -2.237e+04  7.183e+03  -3.114 0.001858 ** 
## Store23:Temperature        -2.236e+04  7.949e+03  -2.813 0.004936 ** 
## Store24:Temperature        -2.047e+04  7.549e+03  -2.711 0.006730 ** 
## Store25:Temperature        -9.531e+02  1.647e+03  -0.579 0.562833    
## Store26:Temperature        -2.103e+04  7.620e+03  -2.760 0.005801 ** 
## Store27:Temperature        -2.002e+04  7.233e+03  -2.768 0.005666 ** 
## Store28:Temperature        -2.418e+04  7.805e+03  -3.098 0.001958 ** 
## Store29:Temperature        -2.168e+04  7.380e+03  -2.938 0.003319 ** 
## Store30:Temperature         1.393e+03  1.597e+03   0.872 0.383185    
## Store31:Temperature        -9.609e+01  1.556e+03  -0.062 0.950776    
## Store32:Temperature        -3.923e+03  2.408e+03  -1.629 0.103299    
## Store33:Temperature        -2.398e+04  8.108e+03  -2.958 0.003114 ** 
## Store34:Temperature        -2.301e+04  7.782e+03  -2.957 0.003125 ** 
## Store35:Temperature        -1.808e+04  7.081e+03  -2.553 0.010726 *  
## Store36:Temperature         2.288e+03  1.734e+03   1.320 0.187068    
## Store37:Temperature         1.238e+03  1.799e+03   0.688 0.491267    
## Store38:Temperature        -2.081e+04  7.795e+03  -2.670 0.007608 ** 
## Store39:Temperature         4.433e+03  1.799e+03   2.464 0.013783 *  
## Store40:Temperature        -2.341e+04  7.937e+03  -2.949 0.003205 ** 
## Store41:Temperature        -3.551e+03  2.567e+03  -1.383 0.166698    
## Store42:Temperature        -2.462e+04  8.162e+03  -3.017 0.002567 ** 
## Store43:Temperature         1.953e+03  1.841e+03   1.061 0.288808    
## Store44:Temperature        -2.464e+04  8.213e+03  -3.000 0.002715 ** 
## Store45:Temperature        -8.494e+03  3.100e+03  -2.740 0.006171 ** 
## Store2:Fuel_Price          -1.279e+05  9.121e+04  -1.402 0.161013    
## Store3:Fuel_Price           1.528e+05  1.042e+05   1.467 0.142541    
## Store4:Fuel_Price          -1.163e+06  3.625e+05  -3.209 0.001343 ** 
## Store5:Fuel_Price           5.690e+04  9.934e+04   0.573 0.566781    
## Store6:Fuel_Price          -1.219e+05  9.009e+04  -1.353 0.176048    
## Store7:Fuel_Price          -1.562e+05  1.164e+05  -1.342 0.179706    
## Store8:Fuel_Price           1.191e+05  9.514e+04   1.252 0.210679    
## Store9:Fuel_Price           8.456e+04  9.868e+04   0.857 0.391569    
## Store10:Fuel_Price         -1.152e+06  3.431e+05  -3.359 0.000790 ***
## Store11:Fuel_Price         -2.264e+04  9.614e+04  -0.236 0.813824    
## Store12:Fuel_Price         -9.720e+05  3.181e+05  -3.056 0.002259 ** 
## Store13:Fuel_Price         -9.945e+05  3.648e+05  -2.726 0.006429 ** 
## Store14:Fuel_Price         -2.635e+05  1.389e+05  -1.897 0.057878 .  
## Store15:Fuel_Price         -9.007e+05  3.256e+05  -2.766 0.005692 ** 
## Store16:Fuel_Price         -1.777e+05  1.396e+05  -1.273 0.203240    
## Store17:Fuel_Price         -8.570e+05  3.682e+05  -2.327 0.019987 *  
## Store18:Fuel_Price         -1.048e+06  3.136e+05  -3.341 0.000842 ***
## Store19:Fuel_Price         -8.191e+05  3.248e+05  -2.522 0.011709 *  
## Store20:Fuel_Price         -8.340e+04  9.210e+04  -0.906 0.365221    
## Store21:Fuel_Price          5.369e+04  9.615e+04   0.558 0.576585    
## Store22:Fuel_Price         -9.692e+05  3.062e+05  -3.166 0.001558 ** 
## Store23:Fuel_Price         -9.739e+05  3.584e+05  -2.717 0.006609 ** 
## Store24:Fuel_Price         -1.034e+06  3.214e+05  -3.217 0.001303 ** 
## Store25:Fuel_Price         -5.683e+04  9.235e+04  -0.615 0.538380    
## Store26:Fuel_Price         -9.408e+05  3.255e+05  -2.891 0.003863 ** 
## Store27:Fuel_Price         -9.427e+05  3.098e+05  -3.043 0.002353 ** 
## Store28:Fuel_Price         -1.051e+06  3.166e+05  -3.319 0.000912 ***
## Store29:Fuel_Price         -9.716e+05  3.060e+05  -3.176 0.001505 ** 
## Store30:Fuel_Price          8.151e+04  9.392e+04   0.868 0.385533    
## Store31:Fuel_Price          3.145e+04  9.198e+04   0.342 0.732437    
## Store32:Fuel_Price         -1.776e+05  1.166e+05  -1.523 0.127793    
## Store33:Fuel_Price         -1.013e+06  3.411e+05  -2.971 0.002986 ** 
## Store34:Fuel_Price         -9.641e+05  3.300e+05  -2.922 0.003498 ** 
## Store35:Fuel_Price         -1.001e+06  3.031e+05  -3.303 0.000966 ***
## Store36:Fuel_Price          7.986e+04  9.369e+04   0.852 0.394061    
## Store37:Fuel_Price          9.164e+04  9.742e+04   0.941 0.346923    
## Store38:Fuel_Price         -9.896e+05  3.202e+05  -3.091 0.002009 ** 
## Store39:Fuel_Price         -1.392e+05  1.015e+05  -1.371 0.170295    
## Store40:Fuel_Price         -9.853e+05  3.582e+05  -2.751 0.005967 ** 
## Store41:Fuel_Price         -1.343e+05  1.332e+05  -1.008 0.313403    
## Store42:Fuel_Price         -9.663e+05  3.447e+05  -2.803 0.005084 ** 
## Store43:Fuel_Price          1.520e+04  1.128e+05   0.135 0.892867    
## Store44:Fuel_Price         -9.733e+05  3.644e+05  -2.671 0.007595 ** 
## Store45:Fuel_Price         -2.753e+05  1.372e+05  -2.006 0.044877 *  
## Store2:CPI                  1.211e+04  2.047e+04   0.592 0.554156    
## Store3:CPI                 -2.709e+04  1.598e+04  -1.695 0.090056 .  
## Store4:CPI                  4.033e+04  4.301e+04   0.938 0.348480    
## Store5:CPI                 -2.218e+04  1.657e+04  -1.338 0.180874    
## Store6:CPI                  1.431e+04  1.723e+04   0.830 0.406326    
## Store7:CPI                  1.449e+04  1.938e+04   0.748 0.454515    
## Store8:CPI                 -2.519e+04  1.558e+04  -1.617 0.105962    
## Store9:CPI                 -1.066e+04  1.815e+04  -0.588 0.556861    
## Store10:CPI                -3.190e+04  4.209e+04  -0.758 0.448599    
## Store11:CPI                 1.858e+03  1.444e+04   0.129 0.897659    
## Store12:CPI                 1.128e+04  4.191e+04   0.269 0.787820    
## Store13:CPI                -4.340e+04  5.777e+04  -0.751 0.452532    
## Store14:CPI                -5.200e+04  1.268e+04  -4.100 4.21e-05 ***
## Store15:CPI                -3.142e+04  1.836e+04  -1.712 0.087052 .  
## Store16:CPI                -1.605e+04  1.769e+04  -0.907 0.364212    
## Store17:CPI                -4.300e+04  2.587e+04  -1.662 0.096647 .  
## Store18:CPI                -1.765e+04  2.719e+04  -0.649 0.516227    
## Store19:CPI                -4.748e+04  1.800e+04  -2.637 0.008384 ** 
## Store20:CPI                -7.458e+03  1.133e+04  -0.658 0.510289    
## Store21:CPI                -1.708e+03  2.254e+04  -0.076 0.939616    
## Store22:CPI                 5.513e+03  2.434e+04   0.227 0.820816    
## Store23:CPI                -2.122e+04  3.312e+04  -0.641 0.521823    
## Store24:CPI                 7.683e+03  2.326e+04   0.330 0.741203    
## Store25:CPI                -1.578e+04  1.151e+04  -1.371 0.170489    
## Store26:CPI                -1.509e+04  3.051e+04  -0.494 0.620986    
## Store27:CPI                -2.971e+04  1.832e+04  -1.621 0.105010    
## Store28:CPI                 8.637e+03  4.067e+04   0.212 0.831849    
## Store29:CPI                -3.101e+03  2.592e+04  -0.120 0.904746    
## Store30:CPI                -3.105e+04  2.207e+04  -1.407 0.159455    
## Store31:CPI                 1.122e+04  2.034e+04   0.552 0.581260    
## Store32:CPI                 2.135e+04  1.924e+04   1.109 0.267297    
## Store33:CPI                -1.693e+04  4.149e+04  -0.408 0.683158    
## Store34:CPI                -1.869e+04  2.545e+04  -0.734 0.462807    
## Store35:CPI                -3.146e+04  1.625e+04  -1.936 0.052878 .  
## Store36:CPI                -4.323e+04  2.085e+04  -2.073 0.038202 *  
## Store37:CPI                -2.703e+04  2.019e+04  -1.339 0.180593    
## Store38:CPI                 1.662e+04  4.246e+04   0.391 0.695573    
## Store39:CPI                 4.455e+04  2.315e+04   1.924 0.054397 .  
## Store40:CPI                -2.270e+04  3.392e+04  -0.669 0.503461    
## Store41:CPI                 4.104e+04  2.258e+04   1.817 0.069220 .  
## Store42:CPI                -3.971e+04  4.556e+04  -0.871 0.383531    
## Store43:CPI                -2.290e+04  1.581e+04  -1.448 0.147617    
## Store44:CPI                -4.086e+04  6.065e+04  -0.674 0.500576    
## Store45:CPI                -1.339e+04  1.226e+04  -1.092 0.274719    
## Store2:Unemployment         7.008e+04  1.305e+05   0.537 0.591385    
## Store3:Unemployment        -1.288e+05  1.188e+05  -1.084 0.278621    
## Store4:Unemployment        -3.817e+05  3.910e+05  -0.976 0.328988    
## Store5:Unemployment        -8.773e+04  1.352e+05  -0.649 0.516419    
## Store6:Unemployment         1.464e+05  1.239e+05   1.182 0.237269    
## Store7:Unemployment         8.120e+04  1.719e+05   0.472 0.636615    
## Store8:Unemployment        -1.005e+05  1.281e+05  -0.785 0.432380    
## Store9:Unemployment         6.844e+03  1.364e+05   0.050 0.959995    
## Store10:Unemployment       -4.115e+05  3.989e+05  -1.031 0.302380    
## Store11:Unemployment        4.372e+04  1.100e+05   0.397 0.691193    
## Store12:Unemployment       -3.229e+05  3.954e+05  -0.817 0.414107    
## Store13:Unemployment       -4.297e+05  4.001e+05  -1.074 0.282858    
## Store14:Unemployment       -9.779e+04  2.266e+05  -0.432 0.666021    
## Store15:Unemployment       -2.261e+05  3.853e+05  -0.587 0.557365    
## Store16:Unemployment       -3.768e+04  2.024e+05  -0.186 0.852315    
## Store17:Unemployment       -4.435e+05  3.948e+05  -1.123 0.261371    
## Store18:Unemployment       -3.784e+05  3.800e+05  -0.996 0.319361    
## Store19:Unemployment       -1.133e+05  3.840e+05  -0.295 0.767907    
## Store20:Unemployment       -9.332e+04  1.229e+05  -0.759 0.447812    
## Store21:Unemployment        7.662e+04  1.425e+05   0.538 0.590856    
## Store22:Unemployment       -2.221e+05  3.669e+05  -0.605 0.545062    
## Store23:Unemployment       -3.289e+05  3.946e+05  -0.834 0.404565    
## Store24:Unemployment       -4.183e+05  3.805e+05  -1.100 0.271606    
## Store25:Unemployment       -1.106e+05  1.211e+05  -0.913 0.361153    
## Store26:Unemployment       -3.233e+05  4.183e+05  -0.773 0.439522    
## Store27:Unemployment       -3.273e+05  3.730e+05  -0.877 0.380325    
## Store28:Unemployment       -3.246e+05  3.953e+05  -0.821 0.411584    
## Store29:Unemployment       -3.103e+05  3.734e+05  -0.831 0.406098    
## Store30:Unemployment       -1.456e+05  1.406e+05  -1.036 0.300317    
## Store31:Unemployment        9.781e+04  1.311e+05   0.746 0.455771    
## Store32:Unemployment        1.288e+05  1.664e+05   0.774 0.438959    
## Store33:Unemployment       -3.361e+05  3.977e+05  -0.845 0.398166    
## Store34:Unemployment       -3.651e+05  3.914e+05  -0.933 0.350987    
## Store35:Unemployment        3.699e+02  3.704e+05   0.001 0.999203    
## Store36:Unemployment       -1.357e+05  1.165e+05  -1.165 0.243912    
## Store37:Unemployment       -1.235e+05  1.164e+05  -1.061 0.288727    
## Store38:Unemployment       -3.377e+05  3.947e+05  -0.856 0.392314    
## Store39:Unemployment        8.617e+04  1.291e+05   0.668 0.504436    
## Store40:Unemployment       -3.615e+05  3.951e+05  -0.915 0.360378    
## Store41:Unemployment        2.817e+05  2.188e+05   1.287 0.197998    
## Store42:Unemployment       -3.884e+05  3.993e+05  -0.973 0.330798    
## Store43:Unemployment       -1.796e+05  1.036e+05  -1.734 0.082987 .  
## Store44:Unemployment       -3.874e+05  4.006e+05  -0.967 0.333515    
## Store45:Unemployment       -6.137e+03  2.238e+05  -0.027 0.978125    
## Holiday_Flag1:Temperature   1.647e+03  6.042e+02   2.725 0.006454 ** 
## Holiday_Flag1:Fuel_Price   -3.893e+04  4.691e+04  -0.830 0.406702    
## Holiday_Flag1:CPI          -3.465e+02  5.449e+03  -0.064 0.949297    
## Holiday_Flag1:Unemployment -1.241e+04  2.284e+04  -0.543 0.586931    
## Temperature:Fuel_Price      1.800e+03  6.870e+02   2.620 0.008826 ** 
## Temperature:CPI            -3.030e+02  9.131e+01  -3.319 0.000912 ***
## Temperature:Unemployment   -7.452e+02  3.641e+02  -2.047 0.040767 *  
## Fuel_Price:CPI             -1.273e+04  3.901e+03  -3.264 0.001106 ** 
## Fuel_Price:Unemployment    -4.475e+03  2.261e+04  -0.198 0.843126    
## CPI:Unemployment           -3.004e+03  4.227e+03  -0.711 0.477359    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 151700 on 4277 degrees of freedom
## Multiple R-squared:  0.9321, Adjusted R-squared:  0.9277 
## F-statistic: 210.4 on 279 and 4277 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     => 0.932 
## 
## 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       => 0.93208 
## 
## Step     => 2 
## Removed  => Fuel_Price:Unemployment 
## 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 + CPI:Unemployment 
## R2       => 0.93208 
## 
## Step     => 3 
## Removed  => Holiday_Flag:Unemployment 
## 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 + Temperature:Fuel_Price + Temperature:CPI + Temperature:Unemployment + Fuel_Price:CPI + CPI:Unemployment 
## R2       => 0.93208 
## 
## Step     => 4 
## 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 + Temperature:Fuel_Price + Temperature:CPI + Temperature:Unemployment + Fuel_Price:CPI + CPI:Unemployment 
## R2       => 0.93208 
## 
## Step     => 5 
## 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 + Temperature:Fuel_Price + Temperature:CPI + Temperature:Unemployment + Fuel_Price:CPI 
## R2       => 0.93206 
## 
## 
## No more variables to be removed.
## 
## Variables Removed: 
## 
## => Holiday_Flag:CPI 
## => Fuel_Price:Unemployment 
## => Holiday_Flag:Unemployment 
## => Unemployment 
## => CPI:Unemployment
## 
## Call:
## lm(formula = paste(response, "~", paste(c(include, cterms), collapse = " + ")), 
##     data = l)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -678244  -54709   -9704   32041 1659453 
## 
## Coefficients:
##                             Estimate Std. Error t value Pr(>|t|)    
## (Intercept)               -1.511e+07  3.294e+06  -4.587 4.62e-06 ***
## Store2                    -1.558e+06  5.073e+06  -0.307 0.758825    
## Store3                     4.982e+06  4.008e+06   1.243 0.213933    
## Store4                     1.732e+06  5.954e+06   0.291 0.771172    
## Store5                     3.013e+06  4.032e+06   0.747 0.455027    
## Store6                    -4.094e+06  4.295e+06  -0.953 0.340581    
## Store7                    -3.438e+06  4.758e+06  -0.723 0.469972    
## Store8                     4.263e+06  3.702e+06   1.152 0.249580    
## Store9                     2.253e+05  4.417e+06   0.051 0.959322    
## Store10                    1.349e+07  6.127e+06   2.201 0.027769 *  
## Store11                   -9.379e+05  3.628e+06  -0.259 0.795990    
## Store12                    7.502e+06  4.920e+06   1.525 0.127395    
## Store13                    1.320e+07  8.116e+06   1.626 0.104015    
## Store14                    1.269e+07  3.092e+06   4.105 4.12e-05 ***
## Store15                    9.080e+06  2.879e+06   3.153 0.001625 ** 
## Store16                    2.389e+06  4.311e+06   0.554 0.579537    
## Store17                    1.143e+07  4.024e+06   2.841 0.004519 ** 
## Store18                    9.739e+06  4.806e+06   2.027 0.042771 *  
## Store19                    1.084e+07  2.849e+06   3.805 0.000144 ***
## Store20                    2.978e+06  2.824e+06   1.055 0.291678    
## Store21                   -6.575e+05  5.596e+06  -0.118 0.906465    
## Store22                    4.542e+06  4.473e+06   1.015 0.309935    
## Store23                    7.596e+06  5.002e+06   1.519 0.128907    
## Store24                    6.535e+06  3.111e+06   2.100 0.035760 *  
## Store25                    3.252e+06  2.849e+06   1.142 0.253634    
## Store26                    7.659e+06  5.904e+06   1.297 0.194590    
## Store27                    1.096e+07  2.799e+06   3.916 9.13e-05 ***
## Store28                    8.566e+06  4.713e+06   1.818 0.069179 .  
## Store29                    6.463e+06  4.275e+06   1.512 0.130668    
## Store30                    6.999e+06  5.495e+06   1.274 0.202848    
## Store31                   -2.760e+06  5.046e+06  -0.547 0.584423    
## Store32                   -4.427e+06  4.651e+06  -0.952 0.341190    
## Store33                    8.257e+06  5.997e+06   1.377 0.168572    
## Store34                    9.328e+06  3.757e+06   2.483 0.013073 *  
## Store35                    7.790e+06  2.836e+06   2.747 0.006048 ** 
## Store36                    9.687e+06  4.939e+06   1.961 0.049894 *  
## Store37                    6.195e+06  4.820e+06   1.285 0.198749    
## Store38                    6.365e+06  4.939e+06   1.289 0.197566    
## Store39                   -9.360e+06  5.562e+06  -1.683 0.092457 .  
## Store40                    7.606e+06  5.085e+06   1.496 0.134800    
## Store41                   -1.003e+07  5.642e+06  -1.778 0.075426 .  
## Store42                    1.168e+07  6.578e+06   1.776 0.075769 .  
## Store43                    6.237e+06  3.078e+06   2.027 0.042771 *  
## Store44                    1.047e+07  8.470e+06   1.236 0.216508    
## Store45                    3.545e+06  2.983e+06   1.188 0.234754    
## Holiday_Flag1              6.876e+04  9.586e+04   0.717 0.473213    
## Temperature                6.136e+04  1.907e+04   3.218 0.001299 ** 
## Fuel_Price                 2.091e+06  6.573e+05   3.182 0.001475 ** 
## CPI                        7.699e+04  1.434e+04   5.369 8.33e-08 ***
## Store2:Holiday_Flag1       8.976e+04  8.285e+04   1.083 0.278698    
## Store3:Holiday_Flag1      -6.689e+04  8.143e+04  -0.821 0.411431    
## Store4:Holiday_Flag1       1.216e+05  8.097e+04   1.502 0.133158    
## Store5:Holiday_Flag1      -4.564e+04  8.219e+04  -0.555 0.578708    
## Store6:Holiday_Flag1       2.960e+04  8.388e+04   0.353 0.724146    
## Store7:Holiday_Flag1       8.051e+04  8.444e+04   0.953 0.340407    
## Store8:Holiday_Flag1      -2.754e+04  8.056e+04  -0.342 0.732485    
## Store9:Holiday_Flag1      -2.810e+04  8.555e+04  -0.328 0.742551    
## Store10:Holiday_Flag1      1.183e+05  8.587e+04   1.377 0.168452    
## Store11:Holiday_Flag1     -1.167e+05  8.259e+04  -1.413 0.157871    
## Store12:Holiday_Flag1      6.265e+04  8.123e+04   0.771 0.440586    
## Store13:Holiday_Flag1     -3.582e+04  8.048e+04  -0.445 0.656314    
## Store14:Holiday_Flag1      1.258e+05  8.240e+04   1.527 0.126838    
## Store15:Holiday_Flag1      3.933e+04  7.796e+04   0.504 0.613958    
## Store16:Holiday_Flag1      1.262e+04  7.787e+04   0.162 0.871235    
## Store17:Holiday_Flag1      4.459e+04  9.216e+04   0.484 0.628525    
## Store18:Holiday_Flag1     -4.579e+04  8.732e+04  -0.524 0.600011    
## Store19:Holiday_Flag1     -6.132e+03  8.605e+04  -0.071 0.943191    
## Store20:Holiday_Flag1      1.246e+05  7.920e+04   1.573 0.115696    
## Store21:Holiday_Flag1     -6.059e+03  7.853e+04  -0.077 0.938507    
## Store22:Holiday_Flag1     -4.472e+04  8.485e+04  -0.527 0.598201    
## Store23:Holiday_Flag1      1.168e+05  8.053e+04   1.450 0.147008    
## Store24:Holiday_Flag1      1.073e+05  9.111e+04   1.178 0.238860    
## Store25:Holiday_Flag1     -6.163e+04  8.341e+04  -0.739 0.460025    
## Store26:Holiday_Flag1      5.542e+04  7.856e+04   0.706 0.480520    
## Store27:Holiday_Flag1      2.578e+04  8.446e+04   0.305 0.760211    
## Store28:Holiday_Flag1      3.194e+04  8.452e+04   0.378 0.705537    
## Store29:Holiday_Flag1      5.169e+03  8.772e+04   0.059 0.953014    
## Store30:Holiday_Flag1     -7.115e+04  9.144e+04  -0.778 0.436588    
## Store31:Holiday_Flag1     -1.070e+04  8.027e+04  -0.133 0.893968    
## Store32:Holiday_Flag1      3.022e+04  8.345e+04   0.362 0.717255    
## Store33:Holiday_Flag1     -8.976e+04  9.996e+04  -0.898 0.369260    
## Store34:Holiday_Flag1      7.290e+04  8.468e+04   0.861 0.389346    
## Store35:Holiday_Flag1      2.278e+05  8.710e+04   2.615 0.008957 ** 
## Store36:Holiday_Flag1     -8.897e+04  8.287e+04  -1.074 0.283079    
## Store37:Holiday_Flag1     -9.941e+04  8.779e+04  -1.132 0.257539    
## Store38:Holiday_Flag1     -9.134e+04  8.294e+04  -1.101 0.270840    
## Store39:Holiday_Flag1      4.792e+04  9.012e+04   0.532 0.594953    
## Store40:Holiday_Flag1      1.689e+04  8.394e+04   0.201 0.840530    
## Store41:Holiday_Flag1     -1.876e+04  8.923e+04  -0.210 0.833452    
## Store42:Holiday_Flag1     -8.786e+04  9.890e+04  -0.888 0.374426    
## Store43:Holiday_Flag1     -6.968e+04  8.191e+04  -0.851 0.395006    
## Store44:Holiday_Flag1     -4.699e+04  9.099e+04  -0.516 0.605547    
## Store45:Holiday_Flag1     -8.766e+04  9.076e+04  -0.966 0.334198    
## Store2:Temperature        -1.956e+03  1.579e+03  -1.239 0.215486    
## Store3:Temperature         9.730e+02  1.815e+03   0.536 0.591920    
## Store4:Temperature        -2.828e+04  8.095e+03  -3.494 0.000481 ***
## Store5:Temperature         1.082e+03  1.664e+03   0.650 0.515731    
## Store6:Temperature         1.481e+03  1.643e+03   0.901 0.367443    
## Store7:Temperature        -1.484e+03  2.374e+03  -0.625 0.531972    
## Store8:Temperature        -8.101e+01  1.612e+03  -0.050 0.959929    
## Store9:Temperature         1.344e+03  1.660e+03   0.810 0.418204    
## Store10:Temperature       -3.290e+04  7.925e+03  -4.151 3.37e-05 ***
## Store11:Temperature       -9.130e+02  1.734e+03  -0.527 0.598529    
## Store12:Temperature       -2.276e+04  7.560e+03  -3.010 0.002628 ** 
## Store13:Temperature       -2.587e+04  7.964e+03  -3.248 0.001169 ** 
## Store14:Temperature       -8.075e+03  3.026e+03  -2.669 0.007640 ** 
## Store15:Temperature       -2.242e+04  7.408e+03  -3.027 0.002483 ** 
## Store16:Temperature       -3.527e+03  2.551e+03  -1.382 0.166934    
## Store17:Temperature       -2.399e+04  8.020e+03  -2.991 0.002795 ** 
## Store18:Temperature       -2.110e+04  7.283e+03  -2.897 0.003789 ** 
## Store19:Temperature       -2.197e+04  7.386e+03  -2.975 0.002950 ** 
## Store20:Temperature       -2.148e+03  1.645e+03  -1.306 0.191762    
## Store21:Temperature        1.627e+03  1.595e+03   1.020 0.307842    
## Store22:Temperature       -2.173e+04  6.994e+03  -3.107 0.001900 ** 
## Store23:Temperature       -2.176e+04  7.748e+03  -2.808 0.005002 ** 
## Store24:Temperature       -1.981e+04  7.346e+03  -2.697 0.007031 ** 
## Store25:Temperature       -9.362e+02  1.638e+03  -0.572 0.567540    
## Store26:Temperature       -2.035e+04  7.422e+03  -2.741 0.006144 ** 
## Store27:Temperature       -1.937e+04  7.043e+03  -2.750 0.005985 ** 
## Store28:Temperature       -2.331e+04  7.568e+03  -3.080 0.002080 ** 
## Store29:Temperature       -2.098e+04  7.181e+03  -2.922 0.003496 ** 
## Store30:Temperature        1.421e+03  1.596e+03   0.890 0.373323    
## Store31:Temperature       -8.119e+01  1.556e+03  -0.052 0.958380    
## Store32:Temperature       -3.684e+03  2.361e+03  -1.560 0.118816    
## Store33:Temperature       -2.318e+04  7.883e+03  -2.941 0.003287 ** 
## Store34:Temperature       -2.222e+04  7.561e+03  -2.938 0.003317 ** 
## Store35:Temperature       -1.740e+04  6.890e+03  -2.525 0.011591 *  
## Store36:Temperature        2.273e+03  1.733e+03   1.312 0.189605    
## Store37:Temperature        1.242e+03  1.798e+03   0.691 0.489736    
## Store38:Temperature       -1.994e+04  7.557e+03  -2.639 0.008343 ** 
## Store39:Temperature        4.467e+03  1.798e+03   2.484 0.013018 *  
## Store40:Temperature       -2.280e+04  7.739e+03  -2.946 0.003235 ** 
## Store41:Temperature       -3.366e+03  2.523e+03  -1.334 0.182196    
## Store42:Temperature       -2.381e+04  7.933e+03  -3.001 0.002705 ** 
## Store43:Temperature        2.116e+03  1.823e+03   1.160 0.246027    
## Store44:Temperature       -2.381e+04  7.989e+03  -2.980 0.002899 ** 
## Store45:Temperature       -8.214e+03  3.036e+03  -2.705 0.006847 ** 
## Store2:Fuel_Price         -1.267e+05  9.103e+04  -1.392 0.164032    
## Store3:Fuel_Price          1.520e+05  1.040e+05   1.461 0.144031    
## Store4:Fuel_Price         -9.977e+05  2.815e+05  -3.545 0.000397 ***
## Store5:Fuel_Price          6.226e+04  9.618e+04   0.647 0.517463    
## Store6:Fuel_Price         -1.211e+05  8.852e+04  -1.368 0.171383    
## Store7:Fuel_Price         -1.195e+05  1.098e+05  -1.089 0.276413    
## Store8:Fuel_Price          1.218e+05  9.209e+04   1.323 0.185977    
## Store9:Fuel_Price          8.597e+04  9.623e+04   0.893 0.371700    
## Store10:Fuel_Price        -9.836e+05  2.803e+05  -3.509 0.000454 ***
## Store11:Fuel_Price        -2.278e+04  9.593e+04  -0.237 0.812312    
## Store12:Fuel_Price        -8.160e+05  2.795e+05  -2.919 0.003525 ** 
## Store13:Fuel_Price        -8.257e+05  2.900e+05  -2.847 0.004437 ** 
## Store14:Fuel_Price        -2.073e+05  1.259e+05  -1.647 0.099729 .  
## Store15:Fuel_Price        -7.415e+05  2.642e+05  -2.807 0.005024 ** 
## Store16:Fuel_Price        -1.322e+05  1.164e+05  -1.135 0.256401    
## Store17:Fuel_Price        -6.746e+05  2.853e+05  -2.365 0.018084 *  
## Store18:Fuel_Price        -8.915e+05  2.600e+05  -3.429 0.000612 ***
## Store19:Fuel_Price        -6.588e+05  2.625e+05  -2.510 0.012112 *  
## Store20:Fuel_Price        -6.665e+04  8.871e+04  -0.751 0.452535    
## Store21:Fuel_Price         5.540e+04  9.591e+04   0.578 0.563543    
## Store22:Fuel_Price        -8.171e+05  2.490e+05  -3.281 0.001042 ** 
## Store23:Fuel_Price        -8.010e+05  2.592e+05  -3.090 0.002015 ** 
## Store24:Fuel_Price        -8.707e+05  2.600e+05  -3.349 0.000817 ***
## Store25:Fuel_Price        -4.126e+04  8.919e+04  -0.463 0.643696    
## Store26:Fuel_Price        -7.799e+05  2.622e+05  -2.975 0.002946 ** 
## Store27:Fuel_Price        -7.886e+05  2.501e+05  -3.153 0.001625 ** 
## Store28:Fuel_Price        -8.941e+05  2.776e+05  -3.220 0.001291 ** 
## Store29:Fuel_Price        -8.223e+05  2.615e+05  -3.145 0.001674 ** 
## Store30:Fuel_Price         8.244e+04  9.374e+04   0.879 0.379202    
## Store31:Fuel_Price         3.204e+04  9.183e+04   0.349 0.727186    
## Store32:Fuel_Price        -1.414e+05  1.103e+05  -1.283 0.199677    
## Store33:Fuel_Price        -8.450e+05  2.778e+05  -3.042 0.002366 ** 
## Store34:Fuel_Price        -7.983e+05  2.809e+05  -2.842 0.004503 ** 
## Store35:Fuel_Price        -8.476e+05  2.494e+05  -3.399 0.000682 ***
## Store36:Fuel_Price         8.570e+04  9.250e+04   0.927 0.354201    
## Store37:Fuel_Price         9.572e+04  9.658e+04   0.991 0.321694    
## Store38:Fuel_Price        -8.311e+05  2.816e+05  -2.952 0.003177 ** 
## Store39:Fuel_Price        -1.343e+05  1.006e+05  -1.334 0.182161    
## Store40:Fuel_Price        -8.124e+05  2.588e+05  -3.139 0.001705 ** 
## Store41:Fuel_Price        -9.115e+04  1.152e+05  -0.791 0.428894    
## Store42:Fuel_Price        -7.978e+05  2.820e+05  -2.829 0.004692 ** 
## Store43:Fuel_Price         2.191e+04  1.012e+05   0.216 0.828697    
## Store44:Fuel_Price        -8.040e+05  2.875e+05  -2.797 0.005186 ** 
## Store45:Fuel_Price        -2.184e+05  1.239e+05  -1.763 0.078045 .  
## Store2:CPI                 9.449e+03  2.013e+04   0.469 0.638741    
## Store3:CPI                -2.613e+04  1.595e+04  -1.639 0.101320    
## Store4:CPI                 5.115e+04  4.172e+04   1.226 0.220270    
## Store5:CPI                -1.809e+04  1.578e+04  -1.146 0.251773    
## Store6:CPI                 1.622e+04  1.703e+04   0.952 0.340918    
## Store7:CPI                 1.112e+04  1.879e+04   0.592 0.554007    
## Store8:CPI                -2.097e+04  1.452e+04  -1.444 0.148709    
## Store9:CPI                -6.993e+03  1.752e+04  -0.399 0.689801    
## Store10:CPI               -3.537e+04  4.193e+04  -0.844 0.398993    
## Store11:CPI                2.757e+03  1.441e+04   0.191 0.848331    
## Store12:CPI               -1.184e+04  3.354e+04  -0.353 0.724004    
## Store13:CPI               -4.086e+04  5.759e+04  -0.710 0.478029    
## Store14:CPI               -5.579e+04  1.189e+04  -4.692 2.79e-06 ***
## Store15:CPI               -3.322e+04  1.824e+04  -1.821 0.068646 .  
## Store16:CPI               -1.230e+04  1.669e+04  -0.737 0.461411    
## Store17:CPI               -3.994e+04  2.542e+04  -1.571 0.116189    
## Store18:CPI               -2.217e+04  2.659e+04  -0.834 0.404419    
## Store19:CPI               -4.938e+04  1.787e+04  -2.763 0.005756 ** 
## Store20:CPI               -7.091e+03  1.114e+04  -0.637 0.524276    
## Store21:CPI               -4.317e+03  2.222e+04  -0.194 0.845969    
## Store22:CPI                4.221e+03  2.427e+04   0.174 0.861924    
## Store23:CPI               -1.007e+04  2.977e+04  -0.338 0.735224    
## Store24:CPI                5.479e+03  2.309e+04   0.237 0.812468    
## Store25:CPI               -1.515e+04  1.131e+04  -1.339 0.180629    
## Store26:CPI               -1.476e+04  3.049e+04  -0.484 0.628326    
## Store27:CPI               -3.149e+04  1.822e+04  -1.728 0.084075 .  
## Store28:CPI               -1.491e+04  3.174e+04  -0.470 0.638519    
## Store29:CPI               -8.796e+03  2.439e+04  -0.361 0.718393    
## Store30:CPI               -3.369e+04  2.174e+04  -1.549 0.121394    
## Store31:CPI                8.627e+03  2.001e+04   0.431 0.666454    
## Store32:CPI                1.802e+04  1.866e+04   0.965 0.334472    
## Store33:CPI               -2.168e+04  4.119e+04  -0.526 0.598710    
## Store34:CPI               -2.446e+04  2.332e+04  -1.049 0.294353    
## Store35:CPI               -3.588e+04  1.542e+04  -2.326 0.020044 *  
## Store36:CPI               -4.720e+04  2.012e+04  -2.347 0.018995 *  
## Store37:CPI               -3.061e+04  1.957e+04  -1.564 0.117925    
## Store38:CPI               -7.307e+03  3.399e+04  -0.215 0.829811    
## Store39:CPI                4.078e+04  2.261e+04   1.803 0.071423 .  
## Store40:CPI               -1.141e+04  3.059e+04  -0.373 0.709196    
## Store41:CPI                4.318e+04  2.233e+04   1.933 0.053262 .  
## Store42:CPI               -4.357e+04  4.538e+04  -0.960 0.337052    
## Store43:CPI               -2.874e+04  1.269e+04  -2.264 0.023612 *  
## Store44:CPI               -3.676e+04  6.039e+04  -0.609 0.542788    
## Store45:CPI               -1.724e+04  1.143e+04  -1.508 0.131526    
## Store1:Unemployment        1.235e+05  8.083e+04   1.528 0.126603    
## Store2:Unemployment        1.794e+05  1.079e+05   1.663 0.096358 .  
## Store3:Unemployment       -1.647e+04  9.330e+04  -0.177 0.859893    
## Store4:Unemployment        1.832e+04  4.391e+04   0.417 0.676578    
## Store5:Unemployment        3.741e+04  1.144e+05   0.327 0.743615    
## Store6:Unemployment        2.583e+05  9.996e+04   2.584 0.009796 ** 
## Store7:Unemployment        2.690e+05  1.236e+05   2.176 0.029575 *  
## Store8:Unemployment        1.047e+04  1.037e+05   0.101 0.919602    
## Store9:Unemployment        1.139e+05  1.133e+05   1.005 0.314931    
## Store10:Unemployment      -1.995e+04  7.137e+04  -0.280 0.779833    
## Store11:Unemployment       1.558e+05  8.165e+04   1.909 0.056370 .  
## Store12:Unemployment       6.162e+04  4.168e+04   1.478 0.139371    
## Store13:Unemployment      -3.701e+04  9.498e+04  -0.390 0.696803    
## Store14:Unemployment       1.148e+05  1.602e+05   0.716 0.473744    
## Store15:Unemployment       1.411e+05  1.148e+05   1.230 0.218839    
## Store16:Unemployment       1.582e+05  1.552e+05   1.020 0.307885    
## Store17:Unemployment      -5.313e+04  7.071e+04  -0.751 0.452405    
## Store18:Unemployment      -8.990e+03  1.160e+05  -0.078 0.938201    
## Store19:Unemployment       2.546e+05  1.113e+05   2.287 0.022260 *  
## Store20:Unemployment       6.203e+04  8.330e+04   0.745 0.456538    
## Store21:Unemployment       1.869e+05  1.227e+05   1.524 0.127699    
## Store22:Unemployment       1.409e+05  1.123e+05   1.255 0.209696    
## Store23:Unemployment       5.700e+04  1.281e+05   0.445 0.656330    
## Store24:Unemployment      -5.808e+04  1.230e+05  -0.472 0.636703    
## Store25:Unemployment       4.641e+04  7.960e+04   0.583 0.559902    
## Store26:Unemployment       5.869e+04  1.944e+05   0.302 0.762734    
## Store27:Unemployment       2.689e+04  1.351e+05   0.199 0.842242    
## Store28:Unemployment       5.945e+04  3.934e+04   1.511 0.130803    
## Store29:Unemployment       6.557e+04  7.788e+04   0.842 0.399843    
## Store30:Unemployment      -3.596e+04  1.200e+05  -0.300 0.764430    
## Store31:Unemployment       2.073e+05  1.086e+05   1.909 0.056269 .  
## Store32:Unemployment       3.178e+05  1.162e+05   2.734 0.006280 ** 
## Store33:Unemployment       5.462e+04  6.390e+04   0.855 0.392742    
## Store34:Unemployment       2.961e+04  4.575e+04   0.647 0.517526    
## Store35:Unemployment       3.667e+05  1.107e+05   3.314 0.000929 ***
## Store36:Unemployment      -2.404e+04  9.130e+04  -0.263 0.792359    
## Store37:Unemployment      -9.595e+03  9.152e+04  -0.105 0.916503    
## Store38:Unemployment       4.599e+04  4.115e+04   1.117 0.263863    
## Store39:Unemployment       1.999e+05  1.075e+05   1.859 0.063062 .  
## Store40:Unemployment       2.515e+04  1.289e+05   0.195 0.845273    
## Store41:Unemployment       4.760e+05  1.791e+05   2.658 0.007892 ** 
## Store42:Unemployment       2.039e+03  7.787e+04   0.026 0.979114    
## Store43:Unemployment      -1.693e+04  5.498e+04  -0.308 0.758172    
## Store44:Unemployment       7.250e+03  9.649e+04   0.075 0.940105    
## Store45:Unemployment       2.069e+05  1.563e+05   1.323 0.185780    
## Holiday_Flag1:Temperature  1.622e+03  6.004e+02   2.701 0.006936 ** 
## Holiday_Flag1:Fuel_Price  -2.864e+04  2.723e+04  -1.052 0.292970    
## Temperature:Fuel_Price     1.801e+03  6.811e+02   2.644 0.008228 ** 
## Temperature:CPI           -2.945e+02  8.876e+01  -3.318 0.000913 ***
## Temperature:Unemployment  -7.708e+02  3.560e+02  -2.165 0.030417 *  
## Fuel_Price:CPI            -1.072e+04  3.035e+03  -3.533 0.000416 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 151600 on 4281 degrees of freedom
## Multiple R-squared:  0.9321, Adjusted R-squared:  0.9277 
## F-statistic: 213.6 on 275 and 4281 DF,  p-value: < 2.2e-16

3. 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

4. What is the R^2 of the model (calculated on the validation data)

mean_sales_val <- mean(validationlm$Weekly_Sales)

vallmR2 <- validationlm %>% 
  mutate(res2 = (Weekly_Sales - sales_predicted)^2 , 
         tot2 = (Weekly_Sales - mean_sales_val )^2)

r2 <- 1- sum(vallmR2$res2)/sum(vallmR2$tot2)

mean_sales_val = 1051995.39232258

r2 = 0.91771756274538