At a particular academically challenging high school,the average GPA of a high school senior is known to be normally distributed with a variance of 0.25.A sample of 20 seniors is taken and their average GPA is found to be 2.71.Develop a 90% confidence interval for the population mean GPA.
A)[2.5261,2.8939]
B)[2.5667,2.8533]
C)[2.6180,2.8020]
D)[2.6384,2.7816]

Question

Quizplus · Accepted Answer

The correct answer is A because the confidence interval is calculated as 2.71 +/- 1.96 * sqrt(0.25/20) = [2.5261, 2.8939].

At a Particular Academically Challenging High School,the Average GPA of a High