The mid-distance running coach, Zdravko Popovich, for the Olympic team of eastern European country claims that his six-month training program significantly determine the average time to complete 1500-meter run. Five mid-distance runners were randomly chosen before they were trained with coach Popovich's six-month training program as well as their completion time of 1500-meter run was recorded (in minutes). After six months of training under coach Popovich, the same 5 runners' 1500 meter run time was recorded again results are given below.
Runner 1 2 3 4 5
Completion time before training 5.9 7.5 6.1 6.8 8.1
Completion time after training 5.4 7.1 6.2 6.5 7.8
At an alpha level of .05, can we conclude that there has been a significant decrease in the mean time per mile?