Assume that the heights of female executives are normally distributed. A random sample of 20 femaleexecutives have a mean height of 62.5 inches and a standard deviation of 1.8 inches. Construct a 98%confidence interval for the population variance, $$\sigma ^ { 2 } .$$
A) (1.7, 8.1)
B) (1.3, 2.8)
C) (0.9, 4.5)
D) (1.8, 8.5)

Question

Quizplus · Accepted Answer

The correct answer is A because the 98% confidence interval for the population variance is (1.7, 8.1). This can be calculated using the formula:```[(n-1)*s^2]/X^2_a/2, [(n-1)*s^2]/X^2_(1-a/2)```where n is the sample size, s is the sample standard deviation, and X^2_a/2 and X^2_(1-a/2) are the chi-squared critical values for the desired confidence level.

Assume That the Heights of Female Executives Are Normally Distributed σ2.\sigma ^ { 2 } .σ2.

Assume That the Heights of Female Executives Are Normally Distributed $\sigma ^ { 2 } .$