Exercise

Sleep study data

Researchers enrolled 18 subjects in a sleep deprivation study. Their observed sleep_study data are loaded in the workspace. These data contain the day_0 reaction times and day_3 reaction times after 3 sleep deprived nights for each subject.

You will define and explore diff_3, the observed difference in reaction times for each subject. This will require the mutate() & summarize() functions. For example, the following would add variable day_0_s, day_0 reaction times in seconds, to sleep_study: 

sleep_study <- sleep_study %>% 
    mutate(day_0_s = day_0 * 0.001)

You can then summarize() the day_0_s values, here by their minimum & maximum:

sleep_study  %>% 
    summarize(min(day_0_s), max(day_0_s))

Instructions

100 XP
  • Check out the first 6 rows of sleep_study.
  • Define a new sleep_study variable diff_3, the day_3 minus the day_0 reaction times.
  • Use ggplot() with a geom_histogram() layer to construct a histogram of the diff_3 data.
  • summarize() the mean and standard deviation of the diff_3 observations.