Mean

Recall that the mean of a list x₁,…,x_n is simply their numeric average (x₁+⋯+x_n)/n. The mean command finds the mean of a list.

mean takes one mandatory argument and one optional argument:
- L, a list or matrix of numbers.
- W, a list or matrix of weights, the same size as L.
mean(L ⟨,W⟩) returns the mean of the list or a list with the means of the columns of the matrix.

mean([1,2,3,4])

since (1+2+3+4)/4=5/2.

mean([[1,2,3],[5,6,7]])

⎡
⎣

3,4,5

⎤
⎦

since (1+5)/2=3, (2+6)/2=4 and (3+7)/2=5.

mean([2,4,6,8],[2,2,3,3])

since (2· 2+4· 2+6· 3+8· 3)/(2+2+3+3)= 27/5.

mean([[1,2],[3,4]],[[1,2],[2,1]])

⎡
⎢
⎢
⎣

⎤
⎥
⎥
⎦

since (1· 1+3· 2)/(1+2)=7/3 and (2· 2+4· 1)/(2 + 1)=8/3.