Sampling Error Calculator
Find the sampling error for a sample mean.
Sampling error is the margin by which a sample mean may differ from the true mean.
The math behind it
error = z * (SD / sqrt(n)). Larger samples shrink the sampling error.
Worked example
SD 15, n 100, 95% gives about plus or minus 2.94.
FAQ
How do I reduce it?
Increase the sample size; error falls with the square root of n.