Finding the standard deviation for every single value in a matrix

Hi Everyone,

I have a 10 matrices X1, X2,X3......X10. Each matrix has a size of (512x30).

1- i want to calculate the mean for all , and the output matrix must be in the same size as input (512x30).

2- Then, i want to calculate the standard deviation for all , and the output matrix must be in the same size as input (512x30).

Any help will be apperciated.

[KALYAN ACHARJYA]

It seems Homework. Please share your efforts, so that we can help you.

[KSSV]

Read about functions mean and std.

[Abdulhakim Alezzi]

I have used these functions, i have calculated the mean and std by :

mymean= mean (x);

mystd= std (mymean);

but the output was a matrix of (1x30).

Answer 1

[Matt J]

X=cat(3, X1,X2,X3,X4,X5,X6,X7,X8,X9,X10); %It was a mistake to create 10 separate matrices.

MeansX=mean(X,3),

StdX = std(X,[],3)

[Abdulhakim Alezzi]

Thank you very much. It works perfectly.

Do you have any idea how to find the std if the matrix has 3D size (NxNxM)?

[Matt J]

You mean you have 10 arrays X1,..X10, all of them NxNxM?

[Abdulhakim Alezzi]

yes

[Abdulhakim Alezzi]

X = rand(30,30,512); % Some random data:

B = std(A,[],2); % i got a matrix with 30x1x512.

I want to find get B with a matrix size of 30x30x512.

[Matt J]

Well as before, you should not have 10 separate variables. You should have a 4D array containing all of your data and then just take std() along the 4th dimension, e.g.,

A=rand(30,30,512,10);

B=std(A,[],4);