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e @1011 Espaol 14 15 A researcher studying stress is interested in the blood pressure measurements of chief executive officers (CEOs) of major corporations. He has good reason to believe that the mean systolic blood pressure, p, of CEOs of major corporations is different from 134 mm Hg, which is the value reported in a possibly outdated journal article. He plans to perform a statistical test. He measures the systolic blood pressures of a random sample of CEOs of major corporations and finds the mean of the sample to be 124 mm Hg and the standard deviation of the sample to be 16 mm Hg. 3 Based on this information, complete the parts below. 00 (a) What are the null hypothesis H0 and the alternative hypothesis H1 that should be used for the test? l4 i II] :29 H : I] o L <_l usu l.>lJ 3 H1 :1] DJ |_2_| Lj:|j l_ll:l T (b) Suppose that the researcher decides not to reject the null hypothesis. What sort of error might he be making? (Choose one) V I (C) Suppose the true mean systolic blood pressure of CEOs of major corporations is 120 mm Hg. Fill in the blanks to describe a Type II error. A Type 11 error would be (Choose one) V lthe hypothesis that p. is (Choose one) V ] (Choose one) V when, in fact, ll 15 (Choose one) V - Submit Assignment Espaol 6 9 11 12 14 15 Executives of a supermarket chain are interested in the amount of time that customers spend in the stores during shopping trips. The mean shopping time, p, '3 spent by customers at the supermarkets has been reported to be 38 minutes, but executives have good reason to believe that p. is different from 38 minutes. The executives hire a statistical consultant and ask her to perform a statistical test. To perform her statistical test, the consultant collects a random sample of shopping times at the supermarkets. She computes the mean of these times to be 43 minutes and the standard deviation of the times to be 15 minutes. 00 Based on this information, complete the parts below. j :19 (a) What are the null hypothesis H0 and the alternative hypothesis H1 that should be used for the test? l1 i [1 I H : :I 0 | 9.2 H1 : :I |2_l 2|] Lil] (b) Suppose that the consultant decides to reject the null hypothesis. What sort of error might she be making? (Choose one) V I X 53 (C) Suppose the true mean shopping time spent by customers at the supermarkets is 38 minutes. Fill in the blanks to describe a Type I error. A Type I error would be I(Choose one) V , the hypothesis that p. is I(Choose one) Y II(Choose one) V I when, in fact, [4 is I(choose one) Y I. Espaol 6 9 1o 12 14 15 > According to a leasing firm's reports, the mean number of miles driven annually in its leased cars is 12,260 miles with a standard deviation of 1180 miles. The company recently starting using new contracts which require customers to have the cars serviced at their own expense. The company's owner believes the mean ? number of miles driven annually under the new contracts, p, is less than 12,260 miles. He takes a random sample of 37 cars under the new contracts. The cars in the sample had a mean of 11,858 annual miles driven. Assume that the population is normally distributed. Is there support for the claim, at the 0.10 level of 5!\" significance, that the population mean number of miles driven annually by cars under the new contracts, is less than 12,260 miles? Assume that the population standard deviation of miles driven annually was not affected by the change to the contracts. 00 Perform a one-tailed test. Then complete the parts below. 15:0 Carry your intermediate computations to three or more decimal places, and round your responses as specified below. (If necessary, consult a list of formulas.) IE! (a) State the null hypothesis H0 and the alternative hypothesis H1. ll 0 P El H0:[: i s B H1:l: II] D = (b) Determine the type of test statistic to use. (Choose one) 7 ] :13 5D 2'3 (c) Find the value of the test statistic. (Round to three or more decimal places.) :l'l El (cl) Find the critical value. (Round to three or more decimal places.) (e) Can we support the claim that the population mean number of miles driven annually by cars under the new contracts is less than 12,260 miles? 0 Yes 0 No Submit Assignment /\\ The breaking strengths of cables produced by a certain manufacturer have historically had a mean of 1850 pounds and a standard deviation of 90 pounds. The 1O \"'_ . . X 63 (d) Find the pvalue. (Round to three or more deCImal places.) (e) Can we support the claim that the population mean breaking strength of the newly-manufactured cables is greater than 1850 pounds? OYes O No Submit Assignment Espanol - 2 3 4 5 6 V 7 V 8 9 10 11 12 13 14 15 An electronics manufacturing process has historically had a mean completion time of 65 minutes. It is claimed that, due to improvements in the process, the .U mean completion time, u, is now less than 65 minutes. A random sample of 21 completion times using the new process is taken. The sample has a mean completion time of 60 minutes, with a standard deviation of 11 minutes. Assume that completion times using the new process are approximately normally distributed. At the 0.10 level of significance, can it be concluded that the population mean completion time using the new process is less than 65 minutes? oo Perform a one-tailed test. Then complete the parts below. EO Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.) (a) State the null hypothesis Ho and the alternative hypothesis H1. O P H : 0 X S p H, :0 (b) Determine the type of test statistic to use. (Choose one) V 0=0 OSO 020 (c) Find the value of the test statistic. (Round to three or more decimal places.) 0 00 0 X 5 (d) Find the critical value. (Round to three or more decimal places.) 0 (e) Can it be concluded that the mean completion time using the new process is less than 65 minutes? O Yes ONo Continue Submit AssignmentG) 10 11 12 Espaol 14 15 > A certain brokerage house wants to estimate the mean daily return on a certain stock. A random sample of 10 days yields the following return percentages. -2.78, 0.72, -1.38, 1.72, 0.98, 2.72, -1.63, 1.2, -1.08, -0.98 Send data to calculator Send data to Excel 8 If we assume that the returns are normally distributed, find a 90% confidence interval for the mean daily return on this stock. Give the lower limit and upper limit of the 90% confidence interval. (3'? Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.) Lower limit: Upper limit: J J X 5) Fl l-ll Submit Assignment Espa Hal 6 9 1o 11 12 14 ( 15)) Thanks to an initiative to recruit top students, an administrator at a college claims that this year's entering class must have a greater mean IQ score than that of entering classes from previous years. The administrator tests a random sample of 17 of this year's entering students and finds that their mean IQ score is 112, I? with a standard deviation of 12. The college records indicate that the mean IQ score for entering students from previous years is 110. :I Is there enough evidence to conclude, at the 0.10 level of significance, that the population mean IQ score, 11, of this year's class is greater than that of previous years? To answer, assume that the IQ scores of this year's entering class are approximately normally distributed. 00 Perform a onetailed test. Then complete the parts below. :1 Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.) .10 El (a) State the null hypothesis H0 and the alternative hypothesis H1. l1 O p El H0 : I: _ A x S p H1 : I: II] D Elm E (b) Determine the type of test statistic to use. \"Choose one) Vi _=i'| [35 _Z_' (c) Find the value of the test statistic. (Round to three or more decumal places.) #1 E| I . . X 5:) (d) Find the p-value. (Round to three or more deCImal places.) I] (e) Can we conclude that the mean IQ score of this year's class is greater than that of previous years? OYes O No Submit Assignment