Independent random samples are taken at a university to compare the average GPA
ID: 3048602 • Letter: I
Question
Independent random samples are taken at a university to compare the average GPA of seniors to the average GPA of sophomores. Given a 90% confidence interval for the difference between the true average GPAs (seniors - sophomores) of (-0.85, -0.05), what can you conclude?
1) We are 90% confident that the average GPA of seniors is greater than the average GPA of sophomores.
2) We do not have enough information to make a conclusion.
3) We are 90% confident that the difference between the two sample GPAs falls within the interval.
4) There is no significant difference between the true average GPA for seniors and sophomores.
5) We are 90% confident that the average GPA of seniors is less than the average GPA of sophomores.
Explanation / Answer
Answer: 5) We are 90% confident that the average GPA of seniors is less than the average GPA of sophomores. because both the limits in the CI are negative.