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Statistical function
NORM.S.INV
Returns the inverse of the standard normal cumulative distribution: the z-score for a probability.
OccasionalDifficulty 1400 · AdvancedUsage rank #218 of 520
When to use it
The z-score at a given cumulative probability of the standard normal. The source of every 1.645, 1.96, and 2.326 in a statistics table.
The shape of it
- Syntax
=NORM.S.INV(probability)
- Example
=NORM.S.INV(0.975)
Worked examples
The 1.96
=NORM.S.INV(0.975) → 1.959963985
The 95% two-sided critical value.
Median
=NORM.S.INV(0.5) → 0
The median.
One-sided 99%
=NORM.S.INV(0.99) → 2.326347874
The 99% one-sided value.
Worth knowing
- Returns 1.96 for 0.975, the familiar 95% two-tailed critical value.
- Safety stock multiplier for a service level: NORM.S.INV(service level).
- Value at risk uses NORM.S.INV(1-confidence).
- Random z-scores: NORM.S.INV(RAND()).
Where it goes wrong
- #NUM! for probability of 0, 1, or outside that range.
- Replaces NORMSINV.
Related
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