Given:
Ethan spends;
6 hours every night for 4 weeks on a campus bar
The total number of hours that Ethan spent in the campus bar is determined by:
Total hours spent = 6 hours/day * ( 7 days / week) * ( 4 weeks )
Total hours spent = 168 hours
Therefore, Ethan spent 168 hours on a campus bar to study the effects of alcohol on the behavior of college females.
