Since our data do not approximate the normal distribution, we will perform a non-parametric test.
In general, the descriptive statistics that are shown together with a non-parametric test are not n, mean and standard deviation,
but n, median, percentile 25 and percentile 75.
Adjust the code below to create an R object MVPAbyWalkability
: summarize the MVPA_acc
by Walkability
by calculating the number of cases, the median, percentile 25 and percentile 75 (in that order).