Standard Error: SD = 20, n = 400
With SD = 20 and a large sample of 400, the standard error is 1.0, showing how large samples reduce estimation error.
How to use this tool
- Enter standard deviation (s) and sample size (n) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your standard error (se) and the full breakdown beneath it.
Find the standard error for a large sample of 400 with standard deviation 20, demonstrating the reduction in uncertainty with larger samples.
Frequently asked questions
- What is the difference between standard deviation and standard error?
- Standard deviation (SD) describes the variability of individual data points around their mean. Standard error (SE) describes the variability of the sample mean itself — it shrinks as sample size grows: SE = SD / √n.