How to achieve zero mean and unit variance

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syd 2014-4-13

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评论： Walter Roberson 2017-1-30

I have a matrix 50x3000. How do I achieve zero mean and unit variance

Also How would i normalize the same after applying zero mean and unit variance?

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syd 2014-4-13

Ok sorry for asking in the wrong way. What I meant was once I get zero mean and assign to variable X, then do I dot standard deviation on this variable X, or on the original matrix?

Image Analyst 2014-4-13

You do it on the shifted version of X. Subtracting the mean merely shifts X without narrowing its distribution. So then you divide to narrow or widen the distribution (X) without shifting it (because it's already shifted).

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Nils 2015-11-27

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You can use the zscore function to zero mean / unit variance any array of data.

For a given matrix A,

A = reshape(zscore(A(:)),size(A,1),size(A,2));

will return the matrix A where all elements now follow a zero mean / unit variance distribution.

It is important to linearize A as the input to zscore, then reshape the output, because zscore will operate differently if you feed it an N-D array rather than a vector.

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sahana kp 2017-1-30

在 MATLAB Online 中打开

@Walter Roberson Now getting the answer like this >> mean(cA3)

ans =

Columns 1 through 5
     -2.72183709262942e-16     -2.72183709262942e-16     -2.72183709262942e-16     -2.72183709262942e-16     -2.72183709262942e-16
Column 6
     -2.72183709262942e-16

>> var(cA3)

ans =

Columns 1 through 5
          1.02777777777778          1.02777777777778          1.02777777777778          1.02777777777778          1.02777777777778
Column 6
          1.02777777777778
is this nomalized ?