Mean

A set of 80 students took a reaction test. The times, t seconds, were grouped as follows:

0 < t ≤ 1 : 10 students
1 < t ≤ 2 : 26 students
2 < t ≤ 3 : 30 students
3 < t ≤ 4 : 14 students

Estimate the mean reaction time.