A simple random sample of size n from population?

A simple random sample of size n is drawn from a population that is known to be normally distributed. The sample variance, s", is determined to be 12.5. Complete parts (a) through (c). The lower bound is . (Round to two decimal places as needed.) The upper bound is . (Round to two decimal places as needed.) (b) Construct a 90% confidence interval for of if the sample size, n, is 30. The lower bound is . (Round to two decimal places as needed.) The upper bound is . (Round to two decimal places as needed.) How does increasing the sample size affect the width of the interval? The width increases The width decreases O The width does not change (c) Construct a 98% confidence interval for of if the sample size, n, is 20. The lower bound is . (Round to two decimal places as needed.) The upper bound is . (Round to two decimal places as needed.) Compare the results with those obtained in part (a). How does increasing the level of confidence affect the confidence interval? O The width decreases O The width does not change O The width increases Click to select your answer(s). MacBook Pro