Help with Learn R project A/B Testing for ShoeFly.com

Hi there,

Trying the project A/B Testing for ShoeFly.com from Learn R.

Can’t get part 10 & 11 to work.

Have tried it myself and even copied and pasted from the hint tab. Still have the same error each time.

# define b_percentage_by_day here:
b_percentage_by_day <- b_clicks_by_day %>%
  group_by(day) %>%
  mutate(percentage = count/sum(count))
Error: Problem with `mutate()` column `percentage`.
ℹ `percentage = count/sum(count)`.
✖ invalid 'type' (closure) of argument
ℹ The error occurred in group 1: day = "1 - Monday".