A simple random sample of size n is drawn from a population that is known to be normally distributed. The sample​ variance, s squareds2​, is determined to be 11.611.6. Complete parts​ (a) through​ (c). ​(a) Construct a​ 90% confidence interval for sigma squaredσ2 if the sample​ size, n, is 20. The lower bound is 7.317.31. ​(Round to two decimal places as​ needed.) The upper bound is 21.7921.79. ​(Round to two decimal places as​ needed.) ​(b) Construct a​ 90% confidence interval for sigma squaredσ2 if the sample​ size, n, is 30. The lower bound is 7.907.90. ​(Round to two decimal places as​ needed.) The upper bound is 1919. ​(Round to two decimal places as​ needed.) How does increasing the sample size affect the width of the​ interval? The width does not change The width increases The width decreases