Calculating average and standard deviation for element correction factor from excel file

I'm importing data from an excel file. I need to take the average of every of every serial number, then calculate the standard deviation percentage of every serial number. Any ideas how i could do that? Thank you

Answer 1

[fred ssemwogerere]

Hello, this should do nicely;

% Assuming your spreadsheet file is in the current (working) Matlab folder
optns=detectImportOptions('file.xlsx'); % replace the input "file.xlsx" here with the name of your file and extension
% Set variables to import from your file and import as table
optns.SelectedVariableNames={'SerialNumber','RawCounts'};
T=readtable('file.xlsx',optns); % replace "file.xlsx" with the name of your file
% Determine unique serial numbers and corresponding indices
% The unique serial numbers are stored in "C".
[Z,mX,mY]=unique(T.SerialNumber);
% Compute the mean for each unique serial number
avg=accumarray(mY,T.RawCounts,[],@mean);
% Compute the standard deviation for each unique serial number
stdev=accumarray(mY,T.RawCounts,[],@std);
% To calculate the percentage standard deviation or relative deviation, you
% multiply each standard deviation by 100, and divide it by its
% corresponding mean value in array; "avg".
percentdev=(stdev.*100)./avg;

[Lucas Acuna Scafati]

That was very helpful, but the avg, stdev, and percentdev don't seem to show in order. Also how can I create a new table that displays 'serial numbers' and 'percentdev'.

Again, thank you for your help.

[fred ssemwogerere]

Hello, add this to the 4th line of code above (comments not included);

[Z,mX,mY]=unique(T.SerialNumber,'stable');
% This will ensure the order in which your serial numbers appear in the spreadsheet program is maintained
% This way the avg, stdev, and percentdev should appear in order

% To create a table of serial numbers and "percentdev"
Tbl=table(Z,percentdev);
% Table column headers
Tbl.Properties.VariableNames={'Serial_Numbers' 'Percent_Std'};

[Lucas Acuna Scafati]

Thank you very much that worked perfectly.

One more question...

What is "C" or by that did you mean "Z"?

% The unique serial numbers are stored in "C".

[Z,mX,mY]=unique(T.SerialNumber);

[fred ssemwogerere]

Hello, oh yes, by "C", i meant "Z". That was a typing error. Thank you