1.

Watch Corporation of Switzerland claims that its watches on average will neither gain nor lose time during a week. A sample of 18 watches provided the following gains (+) or losses (-) in seconds per week. Is it reasonable to conclude that the mean gain or loss in time for the watches is O? -0.10 -0.10 0.30 -0.32 0.20 -0.23 -0.20 0.25 -0.10 -0.37 -0.61 -0.40 -0.20 -0.64 -0.40 0.1 0 -0.68 -0.30 (a) State the decision rule for 0.02 significance level. a (Negative amounts should be indicated by a minus sign) - (Round your answers to 3 decimal places) Reject Hozp=0ifr (b) Compute the Value of the test statistic. 0 (Negative amount should be indicated by a minus sign) 0 (Round your answer to 2 decimal places) Test Statistic t= (c) What is your decision regarding the null hypothesis? V ........................................... 3 Therefore the evidence supports the claim that; V' F-Test for equalityifmpulation variances Arbitron Media Research Inc. conducted a study of the iPod listening habits of men and women. One facet of the study involved the mean listening time. It was discovered that the mean listening time for men was 40 minutes per day. The standard deviation of the sample of the 13 men studied was 10 minutes per day. The mean listening time for the 11 women studied was also 40 minutes, but the standard deviation of the sample was 14 minutes. At the 0.02 significance level perform an F-Test to see if the womens variance is different to the mens variance Compute the value of the test statistic. (a)(Round your answer to 2 decimal places) Test Statistic = (b) What is your decision regarding the Null (Ho : 012 : 0'3) ? .......................................................... i V Ho Do not reject Reiect What is the critical Fvalue for a sample of 8 observations in the numerator and 8 in the denominator? Use a two-tailed test and the 0.02 significance level. F= l (state to 2d p) What is the critical Fvalue for a sample of 7 observations in the numerator and 6 in the denominator? Use a two-tailed test and the 0.1 signicance level. F=| I (state to 21:! p) What is the critical Fvalue for a sample of 16 observations in the numerator and 10 in the denominator? Use a two-tailed test and the 0.02 significance level. F= (state to de) Four brands of lightbulbs are being considered for use in the final assembly area of the Ford F-150 truck plant in Dearborn, Michigan. The director of purchasing asked for samples of 100 from each manufacturer. The numbers of acceptable and unacceptable bulbs from each manufacturer are shown below. At the 0.10 significance level. is there a difference in the quality of the bulbs? (Round your answers to 3 decimal places) Manufacturer A B C D Unacceptable 5 19 18 11 Acceptable 95 81 82 89 Total 100 100 100 100 Ho: There is no relationship between quality and manufacturer. H1: There is a relationship. Reject Ho if x2> ' 2 . =1 l V ' Ho. There is V evidence to indicate that there is a relationship between quality and manufacturer. a The safety director of Honda USA took samples at random from company records of minor work-related accidents and classified them according to the time the accident took place. Number of Number of Time Accidents Time Accidents 8 up to 9 A.M. 15 1 up to 2 P.M. 6 9 up to 10 A.M. 9 2 up to 3 P.M. 19 10 up to 11 A.M. 11 3 up to 4 P.M. 10 11 up to 12 P.M. 8 4 up to 5 P.M. 5 Using the goodness-of-fit test and the 0.05 level of significance, determine whether the accidents are evenly distributed throughout the day. (Round your answers to 3 decimal places) H : The accidents are evenly distributed throughout the day. H : The accidents are not evenly distributed throughout the day. Reject H ifx > [tables) (state accurate to 2dp) Ho. There is evidence to indicate that the accidents are not evenly distributed throughout the day.A study was conducted to determine if there was a difference in the humor content in British and American trade magazine advertisements. In an independent random sample of 287 American trade magazine advertisements, 65 were humorous. An independent random sample of 184 British trade magazines contained 42 humorous ads. (a) State the decision rule for . 10 significance level: Ho: TA = ng H,: A # ng . (Negative values should be indicated by a minus sign) . (Round your answers to 2 decimal places) Reject H if z (b)Compute the value of the test statistic. . (use 3 dp in your calculation of pooled variance, see formula sheet on ELE. but otherwise don't round intermediate numbers) . (Negative values should be indicated by a minus sign) . (Round your answer to 2 decimal places) Test Statistic= Does this data provide evidence that there is a difference in the proportion of humorous ads in British versus American trade magazines? Use the . 10 significance level. H There is evidence to indicate that there is a difference in the proportion of hi insufficient itish versus American trade magazine sufficientA cell phone company offers two plans to its subscribers. At the time new subscribers sign up, they are asked to provide some demographic information. The mean yearly income for a sample of 40 subscribers to Plan A is $45,200 with a standard deviation of $9,000. For a sample of 25 subscribers to Plan B, the mean income is $53,400 with a standard deviation of $7,300. At the 0.05 significance level, is it reasonable to conclude the mean income of those selecting Plan B is larger? Him: For the calculations, assume the Plan A as the first sample and you may assume that the plans have similar variance. The test statistic is '(Round your answer to 2 decimal places) g" ................................................ ' V The Null (Ho: That the means are the same) Reject Do not reject The decision is A coffee manufacturer is interested in whether the mean daily consumption of regular- coffee drinkers is less than that of decaffeinated-coffee drinkers. Assume the population standard deviation for those drinking regular coffee is 1.36 cups per day and 1.51 cups per day for those drinking decaffeinated coffee. A random sample of 50 regular-coffee drinkers showed a mean of 4.28 cups per day. A sample of 43 decaffeinated-coffee drinkers showed a mean of 5.29 cups per day. Use the .05 signicance level. a) This is a V tailed test b) The decision rule is to reject H0: \"reg: pdecaif2