Reconsider Exercises 7.2.33 and 7.2.34 on braking reaction time. If you haven’t done so, put the data file BrakeReactionTime in the Matched Pairs applet and do at least 1,000 randomizations. 

a. Using the 2SD method, determine an approximate 95% confidence interval for the mean difference in braking reaction time between looking at Facebook and Instagram (Facebook – Instagram). 

b. Based on the confidence interval, is there strong evidence that there is, on average, a difference in the average breaking reaction time between looking at text (Facebook) and looking at pictures (Instagram) on the phone? Explain why or why.

Data from Exercise 7.2.33

Researchers at Arizona State University (McNabb & Gray, 2016) explored the effects on driving with various types of cell phone use. In particular, they were interested in comparing the effects between text-based media and picture-based media. They had their subjects use a driving simulator and requested that they stay two seconds behind the car in front of them. The car in front traveled between 55 and 65 mph and was programmed to come to a complete stop eight times during the simulation. One of the variables they measured was the reaction time for the subjects to brake when the car in front of them stopped. They measured this when the subjects were instructed to scroll through Facebook messages that consisted of just text. They also measured this when the subjects were instructed to scroll through Instagram pictures that did not contain any text. The order of the conditions was randomized. The results, in seconds, are in the file BrakeReactionTime. We want to decide whether there is a difference in the average braking reaction time when looking at text (Facebook) on your phone while driving and looking at pictures (Instagram) on your phone while driving.