Question

A sample of 25 observations selected from a normally distributed population produced a sample variance of 32. Construct a confidence interval for σ² for each of the following confidence levels and comment on what happens to the confidence interval of σ²when the confidence level decreases.

Round your answers to 1 decimal place.

a. 1 – α = 0.99

lower (?) to upper (?)

b. 1 – α = 0.95

lower (?) to upper (?)

c. 1 – α = 0.90

lower (?) to upper (?)

As the confidence level decreases, the confidence interval for σ² Choose your answer; As the confidence level decreases, the confidence interval (decreases or increases) in width.

Answer 1