Types of mean
From SubSurfWiki
Main article: Average
With Python code for an arraylike a.
Mean  Remarks  NumPy function  SciPy function 

Arithmetic^{[1]}  the sum divided by the population size, n — used when the sum is of interest  numpy.mean(a) 

Geometric ^{[1]}^{[2]}  the nth root of the product — used when the product is of interest  scipy.stats.mstats.gmean(a)
 
Harmonic ^{[1]}  n divided by the sum of the reciprocals — used for rates and ratios  scipy.stats.mstats.hmean(a)
 
Quadratic or RMS  the square root of the arithmetic mean of the squares — used for magnitudes  np.sqrt(np.mean(a**2)) 
 ↑ ^{1.0} ^{1.1} ^{1.2} Pythagorean means, for which A ≥ G ≥ H
 ↑ Only defined for positive numbers
See also
External links
 What do you mean by average? — blog post at Agile Geoscience