Math Question #6

Question

Suppose we take a sample of size 229 from a population with p = 0.71.

What is the standard deviation of the sampling distribution? 

Part 2:

Suppose you want to lower the standard deviation to 0.01, what sample size would be needed?

n = 

Answer 1

a) standard deviation = sqrt(p * (1-p)/n) = sqrt(0.71 * 0.29/229) = 0.03

b) standard deviation = 0.01 = sqrt((0.71 * 0.29)/n)

0.0001 = 0.71 * 0.29/n

0.0001 * n = 0.71 * 0.29

n = 2059