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I’m confused on a few of these questions and would appreciate any help, thank you A cell phone company knows that the mean length of calls for all of its customers in a certain city is 9 minutes. The company is thinking about offering a senior discount to attract new customers but ﬁrst wants to know whether the mean length of calls for current customers who are seniors (65 and over) is longer than for the general customer pool. The only way to identify seniors is to conduct a survey and ask people whether they are over age 65. Using this method, the company contacts a random sample of 160 seniors and records the length of their last call. The sample mean and standard deviation for the 160 calls are 9.5 minutes and 10 minutes, respectively. (a) Do you think the data collected on the 160 seniors are approximately bell-shaped? YES °No V (b) Is it valid to conduct a one-sample t—test in this situation? 9 Yes No V (c) Test the appropriate hypotheses using a = 0.05. Set up the null and alternative hypothesis. Hozy>9vs.Ha:,u<9Hozp=9vs.Ha:yz9 H0_u=9vs.Ha:u<9 OHozp=9vs.Ha:/l>9 J Compute the test statistic for this situation. (Round your answer to two decimal places.) 1″ = Calculate the p»value for the test. (Use technology to calculate the p-value using the unrounded t value. Round your answer to four decimal places.) p-value = The mean wait time at a particular DMV (department of motor vehicles) is 40 minutes. For 45 randomly selected days over three months, a new procedure is implemented to determine whether wait times are lower on average on days when the new procedure is being used. The mean and standard deviation for the 45 days is 39.7 min and 13 min, respectively. Test the appropriate hypotheses using a = 0.05. Set up the null and alternative hypothesis. 0 H0: ,u = 40 vs.Ha: y < 40 7", Ho:[1 > 40 vs.Ha: u < 40 A H0:[1 = 40 vs.Ha: p a 40 7? H0: ,u = 40 vs.Ha: y > 40 J Compute the test statistic for this situation. (Round your answer to two decimal places.) t = -o.22 3: Calculate the p-value for the test. (Use technology to calculate the p-value using an unrounded test statistic value. Round your answer to four decimal places.) p-value = .4143 X Math Statistics and Probability