3. A researcher is interested in whether attending private school leads to better performance compared to attending public school. A sample of 100 students from a private school produced a mean score of 71.30 on a test. The nationwide average for public school students is 75.62 ( =28.0)

3a) Should we use a one tail or two tail test?

3b) What is the null and alternative hypothesis?

3c) What is zcrit for = 0.05 (the cut off for the critical region)?

3d) What is zobt?

3e) What conclusion do you draw?

4. A car factory is testing whether 25 hybrid electric cars (M=76) get more miles compared to non-hybrid cars ( = 65, =24).

4a) Should we use a one tail or two tail test?

4b) What is the null and alternative hypothesis?

4c) What is zcrit for = 0.05 (the cut off for the critical region)?

4d) What is zobt?

4e) What conclusion do you draw?

5. We ask if visual memory for a sample of 25 art majors (M=43) is different than that of the population whom, on a nationwide test, scored = 45, =14.

5a) Should we use a one tail or two tail test?

5b) What is the null and alternative hypothesis?

5c) What is negative value of zcrit for = 0.05 (the cut off for the critical region)?

5d) What is zobt?

5e) What conclusion do you draw?

6. We measure the self-esteem scores of a sample of statistic students, reasoning that this course may lower their self-esteem relative to that of the typical college student ( = 45, =11.35). We obtain the following scores:

44 55 39 17 27 38 36 24 36

6a)What is the sample mean?

6b) What is the sample standard deviation?

6c) Using information from part a, what is the z-score for this sample mean?

6d) What is the null and alternative hypothesis?

6e) What conclusion do you draw (use = 0.05) ?