Find the cumulative probability below, above or between values in a normal distribution.
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Averages, standard deviation, z-scores, normal distributions and probability calculations.
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With mean 100 and standard deviation 15, a value of 115 corresponds to z = 1.
Find the cumulative probability below, above or between values in a normal distribution. The result is intended for quick estimates, checking arithmetic and comparing scenarios. When a result affects a contract, tax filing, medical decision, building-code requirement or other high-stakes situation, verify the result with the appropriate professional or authoritative source.
With mean 100 and standard deviation 15, a score of 115 is one standard deviation above the mean.
Z-scores connect raw values to a normal distribution's reference scale.
Probabilities assume data are approximately normal; real populations can be skewed or multi-modal.
Related tools: Midpoint Calculator · Percentage Change Calculator
Find the cumulative probability below, above or between values in a normal distribution.
Convert x to a z-score using z = (x − mean) ÷ standard deviation, then evaluate the standard normal cumulative distribution.
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