Beginner: How to get age-adjusted Z scores of a variable?

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ShaneS 2017-7-28

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https://ww2.mathworks.cn/matlabcentral/answers/350627-beginner-how-to-get-age-adjusted-z-scores-of-a-variable

回答： Shruti Shivaramakrishnan 2017-7-31

Hi Everyone,

I have a 25 (subjects) x 68 (variables) matrix. I also have a variable called Age (25 x 1). Now, I would like to get the age-adjusted values of the 68 variables. Could someone teach me how to do that please?

Thanks very much!

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Swarooph 2017-7-28

Does the zscores function help? Doc here.

ShaneS 2017-7-29

Hi there,

Thanks. What I am trying to do is to get use MATLAB to get the age-adjusted values of the raw data.

Following that, I will like to transform into Z scores against the mean and SDs from another group.

Thanks for your time.

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Answer 1

Shruti Shivaramakrishnan 2017-7-31

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https://ww2.mathworks.cn/matlabcentral/answers/350627-beginner-how-to-get-age-adjusted-z-scores-of-a-variable#answer_276230

I think the following explanation should help:

zscore(X,flag,dim)

If flag is 0 (default), then zscore scales X using the sample standard deviation...

If flag is 1, then zscore scales X using the population standard deviation

zscore(X,flag,dim) standardizes X along dimension dim

Also, if you would like to use zscore functionality without the Statistics and Machine Learning Toolbox, the following answers discussion might help: https://www.mathworks.com/matlabcentral/newsreader/view_thread/275744

Also the "bsxfun" function can help you combine the two functionalities with bsxfun(@rdivide, bsxfun(@minus, Data, meanvalue), standard deviation value)

mean can be calculated using the "mean" function and standard deviation using "std"