18. Refer to the previous problem. The same study provided a point estimate of 5.5% for the percentage of Americans who averaged two or more alcoholic drinks per day

a) Construct and interpret a 99% confidence interval for the proportion of the population who drink that much

b) Compare the width of this interval to the one in the previous problem

c) By computing values of the standard error off for n=42.000 when = 1.3.5..7..9, explain why it is more difficult to estimate or when it is near .5 than when it is near 0 or 1.