Reconsider Exercise 7.2.37 on time headway variability. If you haven’t done so, copy and paste the data from the file TimeHeadwayVariability into the Matched Pairs applet and do at least 1,000 randomizations. 

a. What is the standardized statistic in this study? 

b. Based on the standardized statistic, is there strong evidence that, on average, there is a difference in the time headway variability between looking at text (Facebook) and looking at pictures (Instagram) on the phone? Explain why or why not.