Grading Summary These are the automatically computed results of your exam. Grades for essay questions, and comments from your instructor, are in the "Details" section below. Date and Time Started: 8/14/2012 11:09:28 PM Time Spent: 37 min , 55 secs Points Received: 8 / 40 (20%) Question Type: # Of Questions: # Correct: Multiple Choice 10 2 Grade Details - All Questions 1. Question : Brian Vanecek, VP of Operations at Portland Trust Bank, is evaluating the service level provided to walk-in customers. Accordingly, his staff recorded the waiting times for 45 randomly selected walk-in customers, and calculated that their mean waiting time was 15 minutes. If Brian concludes that the average waiting time for all walk-in customers is 15 minutes, he is using a/an ________. Student Answer: range estimate statistical parameter interval estimate point estimate exact estimate Points Received: 4 of 4 Comments: 2. Question : Brian Vanecek, VP of Operations at Portland Trust Bank, is evaluating the service level provided to walk-in customers. Accordingly, his staff recorded the waiting times for 64 randomly selected walk-in customers and determined that their mean waiting time was 15 minutes. Assume that the population standard deviation is 4 minutes. The 90% confidence interval for the population mean of waiting times is ________. Student Answer: 14.27 to 15.73 14.18 to 15.82 9.88 to 20.12 13.86 to 16.14 18.12 to 19.87 Points Received: 0 of 4 Comments: 3. Question : The normal distribution is used to test about a population mean for large samples if the population standard deviation is known. "Large" is usually defined as _______. Student Answer: at least 10 at least 5% of the population size at least 30 at least 12 at least 100 Points Received: 0 of 4 Comments: 4. Question : Consider the following null and alternative hypotheses. Ho: p 0.16 Ha: p < 0.16 These hypotheses _______________. Student Answer: indicate a one-tailed test with a rejection area in the right tail indicate a one-tailed test with a rejection area in the left tail indicate a two-tailed test are established incorrectly are not mutually exclusive Points Received: 0 of 4 Comments: 5. Question : A company produces an item that is supposed to have a six inch hole punched in the center. A quality control inspector is concerned that the machine which punches the hole is "outofcontrol" (hole is too large or too small). In an effort to test this, the inspector is going to gather a sample punched by the machine and measure the diameter of the hole. The alternative hypothesis used to statistical test to determine if the machine is outofcontrol is Student Answer: the mean diameter is > 6 inches the mean diameter is < 6 inches the mean diameter is = 6 inches the mean diameter is 6 inches the mean diameter is 6 inches Points Received: 0 of 4 Comments: 6. Question : A researcher is testing a hypothesis of a single mean. The critical z value for a = .05 and a twotailed test is +1.96. The observed z value from sample data is 1.85. The decision made by the researcher based on this information is to _____ the null hypothesis. Student Answer: reject not reject redefine change the alternate hypothesis into restate the null hypothesis Points Received: 0 of 4 Comments: 7. Question : Jennifer Cantu, VP of Customer Services at Tri-State Auto Insurance, Inc., monitors the claims processing time of the claims division. Her standard includes "a mean processing time of 5 days or less." Each week, her staff checks for compliance by analyzing a random sample of 60 claims. Jennifer's null hypothesis is ________. Student Answer: m > 5 s > 5 n = 60 m < 5 m = 5 Points Received: 0 of 4 Comments: 8. Question : Restaurateur Denny Valentine is evaluating two sites, Raymondville and Rosenberg, for his next restaurant. He wants to prove that Raymondville residents (population 1) dine out more often than Rosenberg residents (population 2). Denny plans to test this hypothesis using a random sample of 81 families from each suburb. His null hypothesis is __________. Student Answer: s12 < s22 m1- 2 p1 - p2 = 0 m1 - m2 = 0 s1 - s2 = 0 Points Received: 0 of 4 Comments: 9. Question : Lucy Baker is analyzing demographic characteristics of two television programs, COPS (population 1) and 60 Minutes (population 2). Previous studies indicate no difference in the ages of the two audiences. (The mean age of each audience is the same.) Lucy plans to test this hypothesis using a random sample of 100 from each audience. Her alternate hypothesis is ____________. Student Answer: m1 - m2 < 0 m1 - m2 > 0 m1 - m2 = 0 m1 - m2 0 m1 - m2 = 1 Points Received: 4 of 4 Comments: 10. Question : Maureen McIlvoy, owner and CEO of a mail order business for wind surfing equipment and supplies, is reviewing the order filling operations at her warehouses. Her goal is 100% of orders shipped within 24 hours. In previous years, neither warehouse has achieved the goal, but the East Coast Warehouse has consistently out-performed the West Coast Warehouse. Her staff randomly selected 200 orders from the West Coast Warehouse (population 1) and 400 orders from the East Coast Warehouse (population 2), and reports that 190 of the West Coast Orders were shipped within 24 hours, and the East Coast Warehouse shipped 372 orders within 24 hours. Maureen's null hypothesis is ____. Student Answer: p1 - p2 = 0 m1 - m2 = 0 p1 - p2 > 0 m1 - m2 < 0 m1 - m2 0 Points Received: 0 of 4 Comments: *