To determine if his teaching method increases students' learning, a professor administers a pretest to his class at the beginning of the semester and then a posttest at the end of the semester. The results from10 randomly chosen students are given below. Let Population 1 be the Pretest scores and Population 2 be the Posttest scores.

Test Scores:

Pretest	Post-test
78	94
56	58
89	87
59	89
58	68
79	84
54	66
83	96
71	69
79	81

Step2of2:

Interpret the confidence interval obtained in Step 1.

Answer:

A.) We are 90% confident that the mean decrease in students' test scores from the pretest to the posttest is between 2.9 and 14.3 points for the population of students in this professor's class.

B.) Since the confidence interval does not contain zero, the data do not provide evidence of a significant increase in students' scores using the professor's teaching method at a 90% confidence level.

C.) Since the confidence interval contains zero, the data do not provide evidence of a significant increase in students' scores using the professor's teaching method at a 90% confidence level.

D.) We are 90% confident that the mean increase in students' scores from the pretest to the posttest is between 2.9 and 14.3 points for the population of students in this professor's class.