How to Calculate Z Score Calc
What is Z Score Calc?
A z-score (standard score) expresses a value's distance from the population mean in standard deviation units. z = (x − μ) / σ. Positive z = above average; negative z = below average.
Step-by-Step Guide
- 1z = (x − μ) / σ
- 2Percentile from z-score: use standard normal CDF
- 3z=1.96 → 97.5th percentile
- 4Enables comparison across different measurement scales
Worked Examples
Input
Score 85 · Mean 70 · SD 15
Result
z = 1.0 → 84th percentile
(85-70)/15=1.0; P(Z<1)=84.1%