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 1.5% of the true population proportion. How large of a sample size is required? Do not round mid-calculation. Submit Question

To obtain a sample to estimate a population proportion.

Given Information:

Confidence Level = 95% = 0.95

Margin of Error = 1.5% = 0.015

Let population proportion ($p$) be 0.50

Sample size (n) can be obtained using the formula:

$n={\left(\frac{Z_{\alpha /2}}{M.E}\right)}^2\left(p\times \left(1-p\right)\right)$

where, $p$ is the population proportion, 

           $M.E$ is the margin of error

           $Z_{\alpha /2}$ is the z-critical value at significance level $\alpha =\frac{1-0.95}{2}=0.025$