measure of central tendency harmonic mean Alejandra Gonzalez-Beltran Orlaith Burke Philippe Rocca-Serra The harmonic mean is a kind of mean which is calculated by dividing the total number of observations by the reciprocal of each number in a series. Harmonic Mean = N/(1/a1+1/a2+1/a3+1/a4+.......+1/aN) where a(i)= Individual score and N = Sample size (Number of scores) adapted from wikipedia and https://www.easycalculation.com/statistics/learn-harmonic-mean.php last accessed: 2015-11-04 http://docs.scipy.org/doc/scipy-0.13.0/reference/generated/scipy.stats.mstats.hmean.html http://personality-project.org/r/html/harmonic.mean.html Usage: > harmonic.mean(x,na.rm=TRUE) Arguments: x, a vector, matrix, or data.frame na.rm, na.rm=TRUE remove NA values before processing. https://en.wikipedia.org/wiki/Harmonic_mean https://en.wikipedia.org/wiki/Mean#Harmonic_mean_.28HM.29