Question

The percentage of people not covered by health care insurance was 15.8%. A congressional committee has been charged with conducting a sample survey to obtain more current information.

1. What sample size would you recommend if the committee's goal is to estimate the current proportion of individuals without health care insurance with a margin of error of 0.03? Use a 95% confidence level.
2. Repeat part (a) using a 99% confidence level

Answer 1

a)

here margin of error E =	0.03
for95% CI crtiical Z          =	1.960
estimated prop.=p=	0.1580
required sample size n=	p*(1-p)*(z/E)2=	568

b)

here margin of error E =	0.03
for99% CI crtiical Z          =	2.576
estimated prop.=p=	0.1580
reqd. sample size n=	p*(1-p)*(z/E)2=	981

(if z score is restricted to 2 decimals , above should be 984)