YouTube would like to test the hypothesis that the average length of an online video watched by a user is more than 8 minutes. A random sample of 37 people watched online videos that averaged 8.7 minutes in length. It is believed that the population standard deviation for the length of online videos is 2.5 minutes. YouTube would like to set the significance level to 2%.
a. Write down the null and alternative hypotheses.
b. What is the critical value?
c. Calculate the test statistic.
d. Compare the test statistic with the critical value. Do you reject or fail to reject the null hypothesis?
e. In words, state your conclusion and interpret the results of the hypothesis test. 2