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.

Pretest	Posttest
98	81
79	81
74	57
90	71
81	79
59	61
77	67
62	50
79	67
83	67

Step1of2:

Construct a 90% confidence interval for the true mean difference between the scores to determine if the teaching method increases students' knowledge of the course material.Round the endpoints of the interval to one decimal place, if necessary.

Lower endpoint:

Upper endpoint: