标准分数计算器 — 公式

## How to Calculate a Z-Score

A z-score measures how many standard deviations a score is from the mean.

### Formula

**Z = (Score - Mean) / Standard Deviation**

- Z = 0 means you scored at the average
- Z > 0 means above average
- Z < 0 means below average

计算示例

A student scores 85 in a class with mean 75 and standard deviation 10.

  1. Z-score = (85 - 75) / 10 = 1.0
  2. Points above mean = 85 - 75 = 10
  3. The student is 1.0 standard deviations above the mean.