A sample of 14 commuters in Chicago showed the average of the commuting times was 33.2 minutes. If the standard deviation was 8.3 minutes, find the 95% confidence interval of the true mean.
Answer to relevant QuestionsFor a sample of 24 operating rooms taken in the hospital study mentioned in Exercise 19 in Section 7–1, the mean noise level was 41.6 decibels, and the standard deviation was 7.5. Find the 95% confidence interval of the ...Find the values for each. a. t a / 2 and n = 18 for the 99% confidence interval for the mean b. t a / 2 and n = 23 for the 95% confidence interval for the mean c. t a / 2 and n = 15 for the 98% confidence interval for the ...A local county has a very active adult education venue. A random sample of the population showed that 189 out of 400 persons 16 years old or older participated in some type of formal adult education activities, such as basic ...A researcher wishes to estimate within $25 the average cost of postage a community college spends in one year. If she wishes to be 90% confident, how large of a sample would be necessary if the population standard deviation ...Using the z table (Table E), find the critical value (or values) for each. a. α = 0.05, two-tailed test b. α = 0.01, left-tailed test c. α = 0.005, right-tailed test d. α = 0.01, right-tailed test e. α = 0.05, ...
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