DDP Final Project

Using the mtcars dataset in R, I plot the graph and preliminarily reveal the relationship between (mpg) and car horsepower (hp) controlling the trasmission type (am).

data("mtcars")
str(mtcars)

'data.frame':   32 obs. of  11 variables:
 $ mpg : num  21 21 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 ...
 $ cyl : num  6 6 4 6 8 6 8 4 4 6 ...
 $ disp: num  160 160 108 258 360 ...
 $ hp  : num  110 110 93 110 175 105 245 62 95 123 ...
 $ drat: num  3.9 3.9 3.85 3.08 3.15 2.76 3.21 3.69 3.92 3.92 ...
 $ wt  : num  2.62 2.88 2.32 3.21 3.44 ...
 $ qsec: num  16.5 17 18.6 19.4 17 ...
 $ vs  : num  0 0 1 1 0 1 0 1 1 1 ...
 $ am  : num  1 1 1 0 0 0 0 0 0 0 ...
 $ gear: num  4 4 4 3 3 3 3 4 4 4 ...
 $ carb: num  4 4 1 1 2 1 4 2 2 4 ...

reg <- lm(mpg ~ am + hp, mtcars); summary(reg)

Call:
lm(formula = mpg ~ am + hp, data = mtcars)

Residuals:
    Min      1Q  Median      3Q     Max 
-4.3843 -2.2642  0.1366  1.6968  5.8657 

Coefficients:
             Estimate Std. Error t value Pr(>|t|)    
(Intercept) 26.584914   1.425094  18.655  < 2e-16 ***
am           5.277085   1.079541   4.888 3.46e-05 ***
hp          -0.058888   0.007857  -7.495 2.92e-08 ***
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Residual standard error: 2.909 on 29 degrees of freedom
Multiple R-squared:  0.782, Adjusted R-squared:  0.767 
F-statistic: 52.02 on 2 and 29 DF,  p-value: 2.55e-10