This calculator helps you find the appropriate sample size for estimating the mean of a population that’s normally distributed within a specified margin of error.
You need to provide the confidence interval, the margin of error, and the population standard deviation (σ) below and click the ‘Calculate’ button:
Assuming the population standard deviation to be 10, you need a sample size of:
171
to estimate a mean with 95% confidence and a precision of 1.5
The confidence interval is usually 90%, 95%, or 99%.
The formula to calculate the sample size is:
n = (Zα/2σ/E)2
Where n is the sample size,
Zα/2 is the z critical value, E is the margin of error, and σ is the population standard deviation.
I hope this calculator is useful. Happy analyzing!