Z-score Calculator
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Z-score Calculator
Calculate Z-scores and find probabilities in a normal distribution. A Z-score measures how many standard deviations a value is from the mean.
Result
Z-score Formula and Interpretation
| Formula | Description |
|---|---|
| Z = (X - μ) / σ | Z-score formula |
| X = raw score | The value being standardized |
| μ = mean | Average of the distribution |
| σ = standard deviation | Measure of spread in the distribution |
Z-score Interpretation:
- Z = 0: Value is equal to the mean
- Z > 0: Value is above the mean
- Z < 0: Value is below the mean
- |Z| > 2: Unusual value (outside 95% of data)
- |Z| > 3: Very unusual value (outside 99.7% of data)
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