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Lesson_8_Workbook_Version_F12_Space

# Is 4580 at the 005 level of

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Unformatted text preview: f significance, does this recent experience suggest a decline in spending? Determine and interpret the p ­value for the test. 1 2 3 4 5 6 7 A z-Test of a Me an S ample me an P opula tion st andard dev iation S ample size Hypothesized mean Alpha B 4.20 1.80 18 5.00 0.05 C z St at P(Z<=z) one-tail z Critical one-ta il P(Z<=z) tw o-tail z Critical t wo-tail D -1 .89 0.0 297 1.645 0.0 593 1.960 PROBLEM # 8.13 ­Based on the sample data, a confidence interval has been constructed such that we have 90% confidence that the population mean is between 120 and 180. Given this information, provide the conclusion that would be reached for each of the following hypothesis tests at the ! =0.10 level: a. H0:! =170 versus H1:! b. H0:! =110 versus H1:! c. H0:! =130 versus H1:! d. H0:! =200 versus H1:! ≠170 ≠110 ≠130 ≠200 5 PROBLEM # 8.14 Under what circumstances should the t ­statistic be used in carrying out a hypothesis test for the population mean? PROBLEM # 8.15 For a simple random sample of 40 items, ! =25.9 and s=4.2. At the 0.01 level of significance, test H0:! =24.0 versus H1:! ≠24.0 PROBLEM # 8.16 For a simple random sample of 15 items from a population that is approximately normally distributed, ! =82.0 and s=20.5. At the 0.05 level of significance, test H0:! ≥90.0 versus H1:! <90.0. 6 1 2 3 4 5 6 7 A t-Test of a Mean Sample mean Sample standard deviation Sample size Hypothesized mean Alpha B C 82.0 20.5 15 90.0 0.05 D t Stat P(T<=t) one-tail t Critical one-tail P(T<=t) two-tail t Critical two-tail -1.511 0.076 1.761 0.153 2.145 PROBLEM # 8.17 ­The International Coffee Association has reported the mean daily coffee consumption for U.S. residents as 1.65 cups. Assume that a sample of 38 people from a North Carolina city consumed a mean of 1.84 cups of coffee per day, with a standard deviation of 0.85 cups. In a two ­tail test at the 0.05 level, could the residents of this city be said to be significantly different from their counterparts across the nation? Source: coffeeresearch.org, August 8, 2006. 1 2 3 4 5 6 7 A t-Test of a Mean Sample mean Sample standard deviation Sample size Hypothesized mean Alpha B 1.84 0.85 38 1.65 0.05 C t Stat P(T<=t) one-tail t Critical one-tail P(T<=t) two-tail t Critical two-tail D 1.378 0.088 1.687 0.177 2.026 PROBLEM # 8.18 When carrying out a hypothesis test for a population proportion, under what condition is it appropriate to use the normal distribution as an approximation to the (theoretically correct) binomial distributio...
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