Pedroletti et al. (A-3) reported the maximal nitric oxide diffusion rate in a sample of 15 asthmatic schoolchildren and 15 controls as mean standard error of the mean. For asthmatic children, they reported 3:5 0:4 nL=s (nanoliters per second) and for control subjects they reported 0:7 :1 nL=s.
For each group, determine the following:

(a) What was the sample standard deviation?

(b) What is the 95 percent confidence interval for the mean maximal nitric oxide diffusion rate of the population?

(c) What assumptions are necessary for the validity of the confidence interval you constructed?

(d) What are the practical and probabilistic interpretations of the interval you constructed?

(e) Which interpretation would be more appropriate to use when discussing confidence intervals with someone who has not had a course in statistics? State the reasons for your choice.

(f) If you were to construct a 90 percent confidence interval for the population mean from the information given here, would the interval be wider or narrower than the 95 percent confidence interval? Explain your answer without actually constructing the interval.
(g) If you were to construct a 99 percent confidence interval for the population mean from the information given here, would the interval be wider or narrower than the 95 percent confidence interval? Explain your answer without actually constructing the interval.