Construct the indicated confidence interval for the difference between the two population means. assume that the twosamples are independent simple random samples selected from normally distributed populations. do not assume that thepopulation standard deviations are equal.
a researcher was interested in comparing the gpas of students at two different colleges. independent simple random samples of 8 students from college a and 13 students from college byielded the following gpas.
college a | college b
3.7 | 3.8 2.8
3.2 | 3.2 4.0
3.0 | 3.0 3.6
2.5 | 3.9 2.6
2.7 | 3.8 4.0
3.6 | 2.5 3.6
2.8 | 3.9
3.4 |
construct a 95% confidence interval for μ1-μ2, the difference between the mean gpa of college astudents and the mean gpa of college b students.
(note: x1= 3.1125, x2= 3.4385, s1= 0.4357, s2= 0.5485.)
a. -0.78 < μ1-μ2< 0.13
b. -0.75 < μ1-μ2< 0.10
c. -0.81 < μ1-μ2< 0.15
d. -0.70 < μ1-μ2< 0.057