You want to obtain a sample to estimate a population proportion. Based on previous evidence, you believe the population proportion is approximately p = 0.33. You would like to be 95% confident that your esimate is within 2.5% of the true population proportion. How large of a sample size is required?
n =
Solution :
Given that,
= 0.33
1 - = 1 - 0.33 = 0.67
margin of error = E = 2.5% = 0.025
At 95% confidence level the z is ,
= 1 - 95% = 1 - 0.95 = 0.05
/ 2 = 0.05 / 2 = 0.025
Z/2 = Z0.025 = 1.96
Sample size = n = (Z/2 / E)2 * * (1 - )
= (1.96 / 0.025)2 * 0.33 * 0.67
= 1359
Sample size = 1359
Get Answers For Free
Most questions answered within 1 hours.