You want to obtain a sample to estimate a population proportion. At this point in time, you have no reasonable estimate for the population proportion. You would like to be 95% confident that you esimate is within 3% of the true population proportion. How large of a sample size is required?
Solution :
Given that,
= 0.5
1 - = 1 - 0.5 = 0.5
margin of error = E = 3% = 0.03
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 ( Using z table ( see the 0.025 value in standard normal (z) table corresponding z value is 1.96 )
Sample size = n = (Z/2 / E)2 * * (1 - )
= (1.96 / 0.03)2 * 0.5 * 0.5
= 1067
Get Answers For Free
Most questions answered within 1 hours.