MPG you and me

Cody Leporini and Sergio Martinez

2022-04-27

Reading in the data

## Linear mixed model fit by REML. t-tests use Satterthwaite's method [
## lmerModLmerTest]
## Formula: 
## comb08 ~ displ + drive + cylinders + fuelType1 + year + cylinders:displ +  
##     (1 | make)
##    Data: normalcars
## 
## REML criterion at convergence: 1339.8
## 
## Scaled residuals: 
##     Min      1Q  Median      3Q     Max 
## -2.3019 -0.5118 -0.1064  0.3288  6.2211 
## 
## Random effects:
##  Groups   Name        Variance Std.Dev.
##  make     (Intercept)  0.8984  0.9479  
##  Residual             14.9925  3.8720  
## Number of obs: 242, groups:  make, 15
## 
## Fixed effects:
##                             Estimate Std. Error         df t value Pr(>|t|)    
## (Intercept)               -340.27485   52.16381  231.17836  -6.523 4.29e-10 ***
## displ                       -6.15855    1.08896  230.03176  -5.655 4.59e-08 ***
## driveAll-Wheel Drive         0.59863    1.62040  231.99601   0.369 0.712142    
## driveFront-Wheel Drive       3.13920    1.25789  231.47612   2.496 0.013272 *  
## driveRear-Wheel Drive        0.91405    1.28097  230.91126   0.714 0.476219    
## cylinders                   -1.71129    0.63994  227.69497  -2.674 0.008035 ** 
## fuelType1Premium Gasoline   -8.48482    2.14822  231.36081  -3.950 0.000104 ***
## fuelType1Regular Gasoline   -7.45351    2.01955  230.47926  -3.691 0.000279 ***
## year                         0.19256    0.02568  231.15899   7.498 1.38e-12 ***
## displ:cylinders              0.52375    0.14311  228.35717   3.660 0.000314 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Correlation of Fixed Effects:
##             (Intr) displ  drA-WD drF-WD drR-WD cylndr flT1PG flT1RG year  
## displ        0.005                                                        
## drvAll-WhlD -0.008  0.057                                                 
## drvFrnt-WhD -0.242  0.104  0.680                                          
## drvRr-WhlDr -0.395 -0.047  0.581  0.832                                   
## cylinders   -0.261  0.240  0.079  0.017  0.054                            
## flTyp1PrmmG  0.082 -0.063 -0.015 -0.022 -0.044 -0.111                     
## flTyp1RglrG  0.011 -0.097 -0.009  0.008  0.024 -0.103  0.926              
## year        -0.998 -0.039 -0.015  0.217  0.378  0.221 -0.113 -0.043       
## dspl:cylndr  0.148 -0.850 -0.032 -0.033  0.002 -0.682  0.089  0.113 -0.104
## $make
##            (Intercept)
## Chevrolet   0.57784454
## Ford       -0.19158763
## Honda      -0.36348392
## Hyundai     0.45468666
## Kia        -0.80859908
## Mazda      -0.45919538
## MINI        0.04612310
## Mitsubishi -0.39313936
## Nissan      0.31325589
## Peugeot    -0.23710117
## Saturn     -0.03970037
## Subaru      0.21683824
## Suzuki     -0.21047855
## Toyota      1.64147280
## Volkswagen -0.54693575
## 
## with conditional variances for "make"
## List of 1
##  $ make:'data.frame':    15 obs. of  1 variable:
##   ..$ (Intercept): num [1:15] 0.578 -0.192 -0.363 0.455 -0.809 ...
##   ..- attr(*, "postVar")= num [1, 1, 1:15] 0.209 0.296 0.505 0.489 0.562 ...
##  - attr(*, "class")= chr "ranef.mer"
## $make

## $make