Exercise

Effect of membership and weekday

Expanding on the previous plot, let's add one more variable into our summary, adding a facet dimension for whether or not the rider is a member of BIXI.

Instructions

100 XP

Compute the number of rides, n for each combination of start week, start hour of day, weekday, and membership.
Use points to plot n on the y-axis and start_wk on the x-axis and color the points by weekday.
Facet using facet_grid() to vary start_hod across columns and membership across rows.