Question

7.3 (9) Basic Computation, Sample Size. What is the minimal sample size needed for a 95% confidence interval to have a maximal margin of error of 0.1.

a) If a preliminary estimate of p is 0.25?

b) If there is no preliminar6 estimate for p?

Never mind I got the answer. Thank you

Answer 1

a)

here margin of error E =	0.100
for95% CI crtiical Z          =	1.960
estimated proportion=p=	0.250
required sample size n =	p*(1-p)*(z/E)2=	73.00

b)

here margin of error E =	0.100
for95% CI crtiical Z          =	1.960
estimated proportion=p=	0.500
required sample size n =	p*(1-p)*(z/E)2=	97.00