hypothesis Testing a Mean

Practice Exam Part II For each problem, And: 1. Null, Alternate Hypothesis, type of test & level of signincance ( ) Check the conditions Compute the sample best statistic, draw a picture and find the Pvalue 4. State the conclusion about the Null Hypothesis. 5. Interpret the conclusion. 6. Last year, the mean running time for a certain type of flashlight battery was 8.5 hours. Assume that q = 0 5 hours. This year, the manufacturer has introduced a change in the production method which he hopes will increase the mean running time. A random sample of 40 of the new light bulbs was obtained and the mean running time was found to be 8.7 hours. Do the data provide sufficient evidence to conclude that the mean running time of the new light bulbs is larger than last year's mean of 8.5 hours? Complete the test with a significance level of 5%. A large software company gives job applicants a test of programming ability and the mean for that test has been 160 in the past. Twenty-five job applicants are randomly selected from one large university and they produce a mean score of 183. Assume that o =12. Use a 0.05 level of significance to test the claim that this sample comes from a population with a mean score greater than 160. Assume normal distribution