10.145 George Johnson is the head coach of a college football team that trains and competes at home on artificial turf. George is concerned that the 40-yard sprint time recorded by his players and others increases substantially when running on natural turf as opposed to artificial turf. If so, there is little comparison between his players’ speed and those of his opponents whenever his team plays on grass. George’s next opponent plays on grass, so he surveyed all the starters in the next game and obtained their best 40-yard sprint times. He then compared them with the best times turned in by his own players. The results are shown in the table that follows:

Player Group n Mean (sec) Std. Dev.

Artificial turf 22 4.85 0.31 Grass 22 4.96 0.42 Do Coach Johnson’s players have a lower mean sprint time? Assuming normality, test at the 0.05 level of significance to advise Coach Johnson.

a. Solve using the p-value approach.

b. Solve using the classical approach.