agg_sleep_weekday: A function to preprocess sleep data for the Person object.
Description
Preprocesses data to be used by the plot_sleep_weekday()
function. Specifically, it calculates the sleep duration and time asleep for
each day of the week (in hours).
Usage
agg_sleep_weekday(person)
Arguments
person
An instance of the Person class
Value
A tidy data frame with the columns weekday, measure, and hours