HARMEAN(b1, b2, ...)
HARMEAN returns the harmonic mean of the N data points (that is, N divided by the sum of the inverses of the data points).
Let us assume that the cells A1, A2, ..., A5 contain numbers 11.4, 17.3, 21.3, 25.9, and 40.1. Then
HARMEAN(A1:A5) equals 19.529814427.