The surgeon referenced in Exercise 4.3 is concerned about the variability of time to full feeding in neonates. Even if the mean is satisfactory, if the variability is too large, the outlying neonates on the longer side of the scale would be at risk. Recall that n = 20, m = 6.56 hours, and s = 4.57 hours. Establish 95% confidence intervals on

(a) the variance and

(b) the standard deviation.