How it works
z=(observed value−mean)/population standard deviation.
Input definitions
- Observed value
- Enter the value in the labeled unit.
- Population mean
- Enter the value in the labeled unit.
- Population standard deviation
- Enter the value in the labeled unit.
A worked example
- Observed value
- 85
- Population mean
- 70
- Population standard deviation
- 10
1.500000
Assumptions & limits
Mathematical calculation using the stated inputs; not a measurement guarantee.
Sources & review
Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.
Method updated 2026-10-17. Content checked against the stated method and examples. Our verification approach.
Common questions
Why can statistical results differ between tools?
Denominator, interpolation and boundary conventions can differ. Use the method and assumptions on this page to compare the same definition; displayed decimals may also be rounded.
How does the Z-score standardization tool work?
z=(observed value−mean)/population standard deviation.
What are the assumptions and limits of Z-score standardization?
Mathematical calculation using the stated inputs; not a measurement guarantee.