You want to obtain a sample to estimate a population proportion.

Question

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 98% confident that your estimate is within 2% of the true population proportion. How large of a sample size is required?

n = 

Do not round mid-calculation. However, use of a critical value rounded to three decimal places will suffice.

Answer 1

To find the sample size we have to determine 98% confidence interval from the statistical table that is the standard normal tables which is 0.02 which gives 2.33 from the table. Also the margin of error or error given is 2% which is equivalent to 0.02 . Using proportion of 0.25.

sample size = 0.25 * (2.33/0.02)^2 = 3393.0625

sample size = 3393