Past experience indicates that monthly data use from mobiles is normally distributed with a mean of 320 MB and a population standard deviation of 128 MB. After an advertising campaign aimed at showing the benefits of a new nationwide 4G network, the manager of a telecommunications firm took a random sample of 16 customers and recorded their montly usage. The manager found the sample average to be 320.96 MB. The manager is looking to conduct a statistical test at the 10% level of significance to determine whether the campaign has changed customers downloading habits.
A) What is the null hypothesis?
B) What is the alternate hypothesis?
C) What is the value of α?
D) What is the value of the test statistic?