An automobile rust proofing company claims that their methodsprotect cars for 60 months. This hypothesis is tested against thealternative that the protection lasts for less than 60 months. Arandom sample of 100 cars produces an average protection time of 57months with a standard deviation of 15 months. a. State the hypotheses in symbols. b. Test the hypothesis using the 5% significance level. c. Find the value of mean(x) necessary to reject the nullhypothesis An automobile rust proofing company claims that their methodsprotect cars for 60 months. This hypothesis is tested against thealternative that the protection lasts for less than 60 months. Arandom sample of 100 cars produces an average protection time of 57months with a standard deviation of 15 months. a. State the hypotheses in symbols. b. Test the hypothesis using the 5% significance level. c. Find the value of mean(x) necessary to reject the nullhypothesis
Explanation / Answer
Given n=100, xbar=57, s=15 (a) The test hypothesis is Ho:>=60 Ha: