Calculate a z-score from a value, mean, and standard deviation, plus its approximate percentile.
The Z-Score Calculator tells you how many standard deviations a value is above or below the mean of its data set.
Z-scores are widely used in statistics to compare values from different distributions and to estimate how unusual or typical a value is.
Z = (x − μ) ÷ σ, where x is the value, μ is the mean, and σ is the standard deviation.
A test score of 85 in a class with a mean of 75 and standard deviation of 8 gives a z-score of 1.25 — meaning the score is 1.25 standard deviations above average, roughly the 89th percentile.
How many standard deviations a data point is from the mean.
z = (value − mean) ÷ standard deviation.
They standardize different data sets onto a common comparable scale.