Dividing set of data into groups and evaluating the mean of each group

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Mohamed Saleh 2018-2-13

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评论： Mohamed Saleh 2018-2-13

Hi. Can any body help me with the following please?. I have a set of random data like x=[-3,-10,-2,...,-7] which is up to let say 5000 values. I need to divide x into set of groups x1, x2, x3, ...,xn, where each group of x has 50 elements. Then I need to evaluate the mean of each group and compare it with the mean of the next group. Thank you in advanced.

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Answer 1

KSSV 2018-2-13

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A = rand(5000,1) ; 
B = reshape(A,50,[]) ;
mean_B = mean(B,2) ;

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Answer 2

Akira Agata 2018-2-13

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在 MATLAB Online 中打开

Another way:

x = rand(5000,1);
g = repelem(1:100,50)';
avg = splitapply(@mean,x,g);

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Mohamed Saleh 2018-2-13

It seems like I am not getting the right value for the mean of each group. Actually I want the first group of x has the first 50 values of x then I find the mean for this group. Then the second group of x has the next 50 values of x and find the mean for this group as well and so on.

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Answer 3

Image Analyst 2018-2-13

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I'm not sure how you're defining/selecting the values to go into each group, but once you have the groups defined, then you can use grpstats() if you have the Statistics and Machine Learning Toolbox.