Please use software R to solve

Consider the built-in data frame cars. Consult the help page to determine the number of observations in the dataset as well as the number of variables. Also, what are the names of the variables? (a) (b) Find the mean stopping distance for all observations for which the speed was 20 miles per hour. Construct a scatterplot relating stopping distance to speed. What kind of rela- tionship do you observe