Session Ready
Exercise

The hist() and truehist() functions

Histograms are probably the best-known way of looking at how the values of a numerical variable are distributed over their range, and R provides several different histogram implementations.

The purpose of this exercise is to introduce two of these:

  • hist() is part of base R and its default option yields a histogram based on the number of times a record falls into each of the bins on which the histogram is based.
  • truehist() is from the MASS package and scales these counts to give an estimate of the probability density.
Instructions
100 XP
  • Use the par() function to set the mfrow parameter for a side-by-side array of two plots.
  • Use the hist() function to generate a histogram of the Horsepower variable from the Cars93 data frame. Set its main argument equal to the title of the plot, "hist() plot".
  • Use the truehist() function to generate an alternative histogram of the same variable. Title this plot, "truehist() plot" by specifying its main argument accordingly.