Two men, A and B, who usually commute to work together decide to conduct an experiment to see whether one route is faster than the other. The men feel that their driving habits are approximately the same, so each morning for two weeks one driver is assigned to route I and the other to route II. The times, recorded to the nearest minute, are shown in the following table. Using this data, find the 95%confidence interval for the true mean difference between the average travel time for route I and the average travel time for route II. Let d=(route I travel time)−(route II travel time)d=(route I travel time)−(route II travel time). Assume that the populations of travel times are normally distributed for both routes. Day M Tu W Th F M Tu W Th F Route I 32 24 28 29 31 29 35 32 24 26 Route II 31 27 24 33 33 33 34 28 23 28   Step 1 of 4: Find the mean of the paired differences, d‾. Round your answer to one decimal place. Step 2 of 4: Find the critical value that should be used in…

A research group studying cell phone habits asked the question “Do you ever use your cell phone to make a payment at a convenience store?” to people selected from two random samples of cell phone users. One sample consisted of older adults, ages 35 years and older, and the other sample consisted of younger adults, ages 18 years to 34 years. The proportion of people who answered yes in each sample was used to create a 95 percent confidence interval of (0.097,0.125)(0.097,0.125) to estimate the difference (younger minus older) between the population proportions of people who would answer yes to the question. Which of the following is the best description of what is meant by 95 percent confidence?     In repeated random sampling with the same sample size, approximately 95% of the sample proportions from the younger group will be between 0.097 and 0.125 greater than the sample proportion from the older group. A In repeated random sampling with the same sample size,…

It was found that in a sample of 90 teenage boys, 70% of them have received speeding tickets. What is the 90% confidence interval of the true proportion of teenage boys who have received speeding tickets? Given the above information, how many boys must be sampled to be within 2% of true proportion in a 90% confidence interval? b. If no information is given for the proportion, how many boys must be sampled?