Question

#15 and #16

Population a00s tion statistics: ơ.-75 and ơ2: 105 tatistics: -2435, 35 and x -2432, 2-90 14. Claim: μι μα α Population statistics: σ1-136 and σ2 -215 mple statistics:5004,n144 and X - 4895, 2 -156 Using and Interpreting Concepts Testing the Difference Between Two Means In Exercises 15-24 (a) identify the claim and state Ho and H. (b) find the critical valuels) and identify the rejection region(s), (c) find the standardized test statistic z, (d) decide wheher to reject or fail to reject the null hypothesis, and (e) interpret the decision in the contexr of the original claim. Assume the samples are random and independent, and the populations are normally distributed 15. Braking Distances To compare the dry braking distances from 60 to miles per hour for two makes of automobiles, a safety engineer con ducts raking tests for 23 models of Make A and 24 models of Make B. The mean braking distance for Make A is 137 feet. Assume the population deviation is 5.5 feet. The mean braking distance for Make B Assume the population standard deviation is 6.7 feet. At a 0.10, can the engineer support the claim that the mean braking distances are different for the two makes of automobiles? (Source: Consumer Reports) standard 16. Digital Gear Shopping To compare customer satisfaction with holiday gift purchases of digital gear from online and walk-in retailers, a researcher randomly selects 30 customer ratings of online retailers and 31 customer ratings of walk-in retailers. The mean customer rating of online retailers is 90 out of 100. Assume the population standard deviation is 3.4. The mean customer rating of walk-in retailers is 88 out of 100. Assume the population standard deviation is 3.5. At α--001, can the researcher support the claim that the mean customer rating of online retailers is greater than the mean customer rating of walk-in retailers? (Source: Consumer Reports) 17. Wind Energy An energy company wants to choose between two regions in a state to install energy-producing wind turbines. A researcher claims that the wind speed in Region A is less than the wind speed in Region B. To test the regions, the average wind speed is calculated for 60 days in each region. The mean wind speed in Region A is 14.0 miles per hour. Assume the population standard deviation is 2.9 miles per hour. The mean wind in Region B is 15.1 miles per hour. Assume the population standard the company support the deviation is 3.3 miles per hour. At a0.05, can t researcher's claim? 18. Repair Costs: Washing Machines You want to buy a washing machine, and a salesperson tells you that the mean repair costs for Model A and Model B are equal. You research the repair costs. The mean repair cost of 24 Model A washing machines is $208. Assume the population standard deviation is $18 The mean repair cost of 26 Model B washing machines is $221. Assume the population salesperson's claim? standard deviation is $22. At a0.01, can you reject the

Answer 1