Question

Why is my P-value wrong?

Suppose that Michael reads somewhere on the Internet that, on average, middle-aged people between 45 and 65 years old visit 12 different websites per day on weekend days. Michael knows that he cannot trust everything he reads on the Internet, so he decides to conduct his own study. He believes that the middle-aged people in his community visit more than 12 websites per day. He surveys a random sample of 15 middle-aged people in his community and asks them to look at their browsing history and count the number of different websites they visited last Saturday. The following stem and leaf plot shows the number of websites visited last Saturday by each person in the survey. The stem unit is tens and the leaf unit is ones. 0 1 1 2 2 5 1 5 1 5 8 1 6 2 6 2 8 4 4 9 Leaf unit = 1 website Michael assumes that the number of websites middle-aged people visit on the weekends is normally distributed, so he decides to perform a t-test with a significance level of =0.05 to test the null hypothesis, Hox = 12 against the alternative hypothesis, H:\> 12, where p is the population mean. If the requirements for a 1-test have not been met, only answer the final question. Otherwise, answer all five of the following questions. First, compute the mean, X, of Michael's sample. Report your answer with two decimals of precision. *= 16,47 websites Then, compute the sample standard deviation, s. Report your answer with two decimals of precision. s= 6.39 websites Next, compute the i-statistic of the test. Report your answer with three decimals of precision. t-statistic = 2.706 Then, use software to calculate the P-value for the test. Report your answer with three decimals of precision. P-value = .00847

Answer 1

Ho: M=12 Himo12 n=15 Test statistic =8-706 fa e & degrees of freedom - of -n-1 =15-1 =10 and DF =14 t=2.706 P-value = P(TSE) =P(T>2.706) 20.008478 50.0080 Rounded, o three decimas P-value = 0.008 dezembro 0.008