How can I get the standard error of each row of a matrix?

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Hello,
I have a 8x30 matrix 'data' and need the mean and standard error of each row. I've figured out the mean
mean_data=mean(data(1:8,:))
but I have no idea about the standard error. I have tried to get the std of the mean, but no matter what I do I just jet the std of the whole matrix, not each row. I've tried for example:
std_mean=std(mean_data,[],2)
or
std_mean=std(mean(data(1:8,:)))
I'm probably really stupid, but I've just started Matlab two weks ago and fail at the easiest things....help would be appreciated!

Answers (1)

Star Strider
Star Strider on 1 Jun 2018
The standard error of the mean (link) is defined as the standard deviation divided by the square root of the number of samples:
std_err_mean = std(data,[],2)/sqrt(size(data,2)); % Standard Error Of The Mean (Row-Wise)
To calculate the 95% confidence intervals, continue with:
mean_data = mean(data,2); % Mean (Row-Wise)
P95 = tinv(0.975, size(data,2)-1); % Compute 95% Confidence Standard Deviation
CI95 = mean(data,2) + std_err_mean*[-1 1]*P95; % 95% Confidence Intervals (Row-Wise)
  1 Comment
hxen
hxen on 29 Feb 2024
You're a very helpful person Star and very much appreciated. Many of you great people on this community have been super helpful.

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