Error when using mean in matlab 2015

I've been trying to use mean(A,2) for a 480 by 10 matrix. It should return a 480 by 1 array but instead returns a 480 by 10 matrix.

Flipping A and using mean(A) results in the following error

"Error using mean (line 3)
Not enough input arguments."

Thought I had a screwed up matrix first but then I tried

A=magic(5)
M=mean(A)

Which resulted in the same error. I can't continue with my code without sorting this out so does anyone know what might have caused this and how to fix?

Thanks in advance

[Stephen23]

You have shadowed the built-in mean function by defining a function or variable with the same name. This is a exactly the reason why you should never use the names of any built-in function for your own variable/function names. Before using any name, check if it already defined using which, and certainly avoid using size, length, mean, i, j, cat, cell, etc for your own varaibles.

Answer 1

[Walter Roberson]

Use

which -all mean

You will find that the first one it locates is one of your own files instead of being in one of MATLAB's toolbox directories such as toolbox/matlab/datafun/mean.m . You need to rename or delete the mean.m that is coming from outside MATLAB (or at least remove the path to it.)