Finding the mean value of a set.

Let's say that I have a set of numbers, for example x= [1 2 4 6 2 7 8 4 5 7 8 9]. I want to calculate the mean value for every 3 numbers. In this case first 1 2 4 , then 6 2 7 and so on. How do I do? should I use any functions?

in fact I have a column containing 180000 numbers. and I want to calculate the mean value for every 50 numbers. Totally 180000/50=3660 mean values. I would appreciate every suggestion.

Answer 1

[Steven Lord]

Original data:

x= [1 2 4 6 2 7 8 4 5 7 8 9]

x = 1×12

1 2 4 6 2 7 8 4 5 7 8 9

Reshape it into a 3-by-whatever matrix. I'll let MATLAB figure out what "whatever" is.

A = reshape(x, 3, [])

A = 3×4

1 6 8 7 2 2 4 8 4 7 5 9

Take the mean in dimension 1 (down the columns.)

m = mean(A, 1)

m = 1×4

2.3333 5.0000 5.6667 8.0000