The authors of the paper “Driven to Distraction” (Psychological Science [2001]: 462–466) describe a study to evaluate the effect of using a cell phone on reaction time. Subjects were asked to perform a simulated driving task while talking on a cell phone. While performing this task, occasional red and green lights flashed on the computer screen. If a green light flashed, subjects were to continue driving, but if a red light flashed, subjects were to brake as quickly as possible and the reaction time (in msec) was recorded. The following summary statis-tics were read from a graph that appeared in the paper:
n = 48 = 530 s = 70
Construct and interpret a 95% confidence interval for m, the mean time to react to a red light while talking on a cell phone. What assumption must be made in order to generalize this confidence interval to the population of all drivers?