Greetings.

Working on “A/B Testing for ShoeFly.com” I’ve found that I can’t find a concise solution for the task 10: For each group ( `a_clicks`

and `b_clicks`

), calculate the percent of users who clicked on the ad by `day`

.

So far I have two solutions:

2.

I think I missed some concept I should use here, but I can’t figure it out.

Could someone give me a hint?

Thanks