What the tool does, how to run it, and what to expect from the result.
z = (x − μ) ÷ σ: how many standard deviations a value sits from the mean. A score of 85 on a test with mean 70 and SD 10 is z = 1.5. Under a normal curve 93.32% of values fall below z = 1.5, so the score is at the 93rd percentile; 6.68% lie above, and the two-tailed p-value is 0.1336.
A quick way to understand who this helps, what it solves, and where it connects next.
Students, teachers, analysts and researchers working with data.
Using the z-score calculator without installing anything or signing up.
Short answers for the questions people usually have before trying a utility like this.
It depends on context. About 68% of values fall within ±1, 95% within ±1.96 and 99.7% within ±3.
Yes: a negative z means the value is below the mean. z = −1 is the 15.9th percentile.
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z = (x − μ) ÷ σ. Probabilities assume a normal distribution.