Question 75554
One survey showed that among 785 randomly selected sunjects who completed four years of college, 18.3% smoke(based on data from American Medical Association). 
a. Construct the 98% confidence interval for the true percentage of smokers among all people who completed four years of college.
--------
E= z*sqrt(pq/n)
You don't have "p" so use p-hat=0.183
E= 2.326sqrt(0.183*0.817/785)
E= 0.032
Then CI is: (0.183-0.032,0.183+0.032) or (0.151,0.215)
==========================

b. Based on the result from part (a),does the smoking rate for those with four year of college appear to be substantially different than the 27% rate for the general population?
Yes, 27% is significantly outside the range of the 98% confidence interval
for the smoking percent of four year college students.
===========
Cheers,
Stan H.