How this calculator works
Range depends on just two extremes. Variance squares each distance from the mean, so large departures carry extra weight; standard deviation returns to the original unit. Mean absolute deviation uses ordinary absolute distances, while IQR describes only the middle half under the selected quartile convention. Relative spread is omitted when the mean is zero and is meaningful chiefly on a ratio scale.
Formula
Range = max - min; variance = Σ(x - mean)²/divisor; MADmean = Σ|x - mean|/n; IQR = Q3 - Q1; quartile deviation = IQR/2.
Worked example
For 1, 2, 3, 4, 5, the range is 4, sample variance is 2.5, mean absolute deviation is 6/5 = 1.2 and linear-interpolated IQR is 2.
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Frequently asked questions
Which result has squared units?
Variance. Range, standard deviation, absolute deviation and IQR retain the data unit.
Which measure resists outliers?
IQR is based on central ranks, so changing one distant extreme often leaves it unchanged. Range and variance can change substantially.
Is mean absolute deviation the same as median absolute deviation?
No. This page averages distances from the mean; median absolute deviation takes the median of distances from the median.