Can a secondary task-such as a word association task- improve your performance when driving while fatigued? This was the question of interest in a Human Factors (May 2014) study. The researchers used a driving simulator to obtain their data. Each of 40 college students was assigned to drive a long distance in the simulator. However, the student-drivers were divided into four groups of 10 drivers each. Group 1 performed the verbal task continuously (continuous verbal condition); Group 2 performed the task only at the end of the drive (late verbal condition); Group 3 did not perform the task at all (no verbal condition); and Group 4 listened to a program on the car radio (radio show condition). At the end of the simulated drive, drivers were asked to recall billboards that they saw along the way. The percentage of billboards recalled by each student-driver is provided in the next table. Use the information in the accompanying SPSS printout to determine if the mean recall percentage differs for student-drivers in the four groups. Test using a = .01.
Data for Exercise 10.38

SPSS Output for Exercise 10.38

Continuous Verbal Radio Show Late Verbal No Verbal ANOVA RECALL Sum of Squares Squares 5921.700 13189.400 Mean Square 1973.900 366.372 Sig. .004 Between Oroups Wihin Oroups Total 5.388 36 39 19111.100