ms. irwin teaches four periods of weight training. she required each student in thr class to record the maximum amount of weight lifted for the squat. based upon the data listed below, which period had the greatest mean score?

period 1 : 100, 100, 125, 125, 130, 130
period 2 : 90, 125, 125, 130, 135, 135
period 3 : 90, 90, 100, 125, 125, 125
period 4: 90, 90 , 90, 100, 100, 125

a. period 1
b. period 2
c. period 3
d. period 4 ​