How to find average and standard deviation in a for loop?

Question

Anu 2022-2-25

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https://ww2.mathworks.cn/matlabcentral/answers/1658120-how-to-find-average-and-standard-deviation-in-a-for-loop

评论： Arif Hoq 2022-2-25

I have a mat file with 70 rows and 11 columns (see the attached). I want to find the mean and standard deviation row-wise with an averaging window of 5. I expected my outcome's dimension as 14x11. As an output, I want to export it as an excel file, where the mean values are 14x11, and the standard deviation is placed next to the mean. I also wanted to add a row in the first row as x, where my x = 0:10:100. For your reference, I have attached the output file. I have written the following code. However, I get it as 14x1, and I understand that the mean is done for 5 rows and 11 columns, but I could not figure it out to fix the issue. May I request you to help me?

avaregedwindow = 5;

[m,n] = size(data_sweep);

k = floor(m/avaregedwindow);

for i = 1: k

p = avaregedwindow*i -(avaregedwindow-1);

y = data_sweep(p:p+(avaregedwindow-1));

mean_y(i, :)= mean(y); %the mistake is here, I guess

sd_y(i, :) = std(y);

end

x = 0:10:100;

meanvalues = vertcat(x, mean_y); % gives error as the dimension does not match

stdvalues = vertcat(x, sd_y); % gives error as the dimension does not match

merge = [mean values, stdvalues];

filename = 'output.xlsx';

writetable(filename, 'merge')

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Answer 1

Arif Hoq 2022-2-25

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https://ww2.mathworks.cn/matlabcentral/answers/1658120-how-to-find-average-and-standard-deviation-in-a-for-loop#answer_904160

编辑：Arif Hoq 2022-2-25

在 MATLAB Online 中打开

you can store your data in a cell array. just export the date in excel using range. and you are indexing upto k=14. but you have k*col =154 data.

A=load('matlab1.mat');
data_sweep=A.data_sweep;
avgwin = 5; 
[row col]=size(data_sweep);
N = size(data_sweep,1);
k = floor(N/avgwin);
C=cell(floor(N/avgwin),size(data_sweep,2));
C1=cell(floor(N/avgwin),size(data_sweep,2));
for i = 1:  k*col
    p = avgwin*i -(avgwin-1);
    y= data_sweep(p:p+(avgwin-1));
    C{i}= mean(y); %the mistake is here, I guess
    C1{i} = std(y);
end
matrix=[C{:}];
mean_y=reshape(matrix,14,11);
matrix1=[C1{:}];
sd_y=reshape(matrix1,14,11);
x = (0:10:100); 
Mean_Data=[x;mean_y];
Sd_Data=[x;sd_y];
writematrix(Mean_Data,'M.xls','Sheet',1,'Range','A1:K20')
writematrix(Sd_Data,'M.xls','Sheet',1,'Range','M1:W20')