Storing regression coefficients in a loop
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Hello,
I'm doing a simple linear regression on a 20x30x365 matrix (latitude, longitude, time). I want to store the slope and p - value for each lat/lon pair such that the end result are two 20x30 matrices. I'm attaching some dummy data and my attempted code below. Thank you. 
X = size(prec,3);
i = 20;
j = 30;
slopes = zeros(i,j);
pvals = zeros(i,j);
for i = 1:i
    for j= 1:j
        mdl = fitlm(X,prec(i,j,:));
        slope = table2array(mdl.Coefficients(2,1));
        pval = table2array(mdl.Coefficients(2,4)); 
        slopes = slope(i,j);
        pvals = pval(i,j);
    end
end
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Accepted Answer
  VBBV
      
      
 on 7 Dec 2021
        
      Edited: VBBV
      
      
 on 8 Dec 2021
  
              slopes(i,j) = slope;
        pvals(i,j) = pval;
2 Comments
  VBBV
      
      
 on 8 Dec 2021
				n = size(prec,3);
X = (1:1:n)';
I = 20;  % change this variable with a differnt letter 
J = 30; % same here 
slopes = zeros(I,J);
pvals = zeros(I,J);
for i = 1:I
    for j= 1:J
        y = reshape(prec(i,j,:),[n,1]);
        mdl = fitlm(X,y);
        slope = table2array(mdl.Coefficients(2,1));
        pval = table2array(mdl.Coefficients(2,4)); 
        slopes(i,j) = slope;
        pvals(i,j) = pval;
    end
end
When the for  loop runs, its using concurrent values of i and j.  Change the symbols as above and run it 
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