Last semester, there were roughly 70 students in SOC 201. The professor took a random sample of 15 of them to understand students' phone habits. Students in the sample had an average of 22 apps on their phones, with a standard deviation of 3. Do students in this semester's SOC 201 class have a different amount of apps on their phones than last semester's students? Assume that students in your lab section right now are a random sample of students from this semester's SOC 201 class. After gathering the number of apps on everyone's phone in this lab section, test the hypothesis that the average number of apps is the same across both classes, using an alpha level of 0.10. (Note: If you don't have a phone with apps, don't worry! You can report '0' or provide the number of apps on your computer desktop instead.)

a. In symbols and words, what is the null hypothesis for this test? What is the alternative?

b. Is this a one-sided or two-sided test? How do you know?

c. Will you use a z-test or a t-test in this situation? Why?

d. What is the value of the test statistic calculated from the sample results?

e. Does evidence suggest that there is a statistically significant difference in number of apps across last semester's class and this semester's class? Explain.