Exercise

Creating histograms in R

In this exercise, you will be analyzing your first real dataset by creating a histogram. Data in R are generally stored in data frames, which are simply tables with rows and columns. The data frame that you will use for this exercise is stored in the variable impact and contains data on how concussions affect the memory capabilities of athletes. The data were collected by testing athletes before and after a concussion, using verbal and visual memory tests, among others. A score on one of these tests ranges from 0 (very bad) to 100 (perfect).

Creating a histogram of a variable in R is made easy with the hist() function. To make your histogram more readable, it's good practice to add a title and labels to the x- and y-axis with the main, xlab and ylab arguments to hist(), respectively.

Instructions

100 XP
  • Take a look at the data frame impact by printing it to the console.
  • Print out summary statistics for each variable using the describe() function. It returns a list of all variables together with some summary statistics.
  • Select the verbal_memory_baseline scores from the data frame and assign them to the variable verbal_baseline. You can select one variable from a data frame by appending $variablename to the name of the data frame.
  • Create a histogram of the verbal_baseline variable. Set "Distribution of verbal memory baseline scores" as the title, "score" as the x-axis label and "frequency" as the y-axis label.