Question

If I have a matrix of values. How do I get the mean of all this values?

Answer 1

add them up and then divide by m*n
where m and n are dimensions of matrix

Answer 2

Yeah I have this in mind, I just wanted to know if there is a mathematical tool that makes that for me. lol. Thanks dumbcow

Answer 3

haha there might be, i dont know

Answer 4

by the way, do you know what variance and covariance means. I mean, what is its physical meaning ...

Answer 5

what do you mean by physical meaning?

Answer 6

I dont know how to say that, but, what I want to know is what is the they represent if I get the covariance, the variance, or even the eigenvectors. I know how to get them but I dont know what information they bring. For example if I derivate a function, I know that what im getting is the slope; in the same way, if I integrate, I know that Im calculation the area under the curve. Does it make sense?

Answer 7

yes
the variance tells you how spread out the data is or how far away you get from the mean
covariance tells you how closely related 2 dependent variables are, if 2 variables are independent then they have a covariance of 0
high covariance means high dependence

Answer 8

Got it! what about eigenvectors and eigenvalues?

Answer 9

its been awhile, im not as good at explaining those
this might help

http://en.wikipedia.org/wiki/Eigenvector