Matrix Averaging

Hi, I'm trying to do something very simple, but can't seem to get the if condition correct.

I want to find the average of (:,2:5) if the values in the first column of the matrix are below a certain average.

Thanks in advance,

Ready to be humbled---

Answer 1

[Matt Fig]

If A is your matrix and tol stands for "a certain average,"

if mean(A(:,1))<tol
   M = mean(A(:,2:5));
end

Answer 2

[Sean de Wolski]

A = rand(5);
A1 = A(:,1);
A1(A1>.5) = mean(A(A1>.5,2:5),2)

Like this? If not, please provide a small example.