How does cell phone use affect driving performance? Strayer, Drews, and Johnston (2003) had undergraduates drive a high-fidelity automobile simulator as their only task and again later while engaged in a hands-free cell phone conversation. Participants applied the brake when the brake lights of the vehicle in front of them came on, producing the reaction times (in seconds) that follow. Calculate d and a 95% confidence interval. Use the confidence interval to test the hypothesis that hands-free cell phone conversations have no effect on reaction time. Write a conclusion. Carry four decimals in your calculations. No cell phone Cell phone 1.03 1.12 0.97 1.31 0.82 0.96 1.09 1.08 1.15 0.99 0.72 1.04 0.95 1.16 0.87 1.22