Question 30 (2.5 points) Let's say you conduct a study in which the amount of coffee consumed by a group of your peers at work is compared to population consumption data collected by Starbucks for all their stores in the U.S. Given that the web site on which you found the Starbucks information gave the mean consumption level, but not the standard deviation, you don't know what the population standard error of the mean is. What test should you use to test for differences between the mean of your group and the mean of the Starbucks population data? Oa. a z test O b. a single sample t test O c. a test for normality Od. analysis of variance