22/02/2021

The mtcars data set

This is one of the most popular data sets in the R community. The data was extracted from the 1974 Motor Trend US magazine, and comprises fuel consumption and 10 aspects of automobile design and performance for 32 automobiles (1973–74 models).

Scope of the app

The presented app includes a boxplot and a regression analysis, where the user can choose the variables, which he can analyse. Also the app provides in a ribbon bar additional information on the mtcars data set.

The summary of the regression model

fit <- lm(mtcars$mpg ~ mtcars$cyl)
summary(fit)
##
## Call:
## lm(formula = mtcars$mpg ~ mtcars$cyl)
##
## Residuals:
##     Min      1Q  Median      3Q     Max
## -4.9814 -2.1185  0.2217  1.0717  7.5186
##
## Coefficients:
##             Estimate Std. Error t value Pr(>|t|)
## (Intercept)  37.8846     2.0738   18.27  < 2e-16 ***
## mtcars\$cyl   -2.8758     0.3224   -8.92 6.11e-10 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 3.206 on 30 degrees of freedom
## Multiple R-squared:  0.7262, Adjusted R-squared:  0.7171
## F-statistic: 79.56 on 1 and 30 DF,  p-value: 6.113e-10
plot(fit)