Error in Loop in a loop

I'm getting this error

Cell contents reference from a non-cell array object.

Error in setParam (line 86)
          N{i}=((19*(TR{i}(t-1,1)))+TR{i}{t,1})/20;

After trying to run this for loop.

for i=1:length(TR)
    for t=length(TR{i})
      if t<21
          N{i}=mean(TR{i}(1:t,1));
      else
          N{i}=((19*(TR{i}(t-1,1)))+TR{i}{t,1})/20;
      end
    end
end

Answer 1

[KSSV]

Try

N{i}=((19*(TR{i}(t-1,1)))+TR{i}(t,1))/20;

Instead of

N{i}=((19*(TR{i}(t-1,1)))+TR{i}{t,1})/20;

[liu James]

Although this works and doesn't give me the error. The answer that it provides isn't what I'm looking for. I'm trying to index each cell and calculate and spit it out. Do you know how I can achieve it?

for i=1:length(TR)
    for t=length(TR{i})
      if t<21
          N{i}{t,1}=mean(TR{i}(1:t,1));
      else
          N{i}{t,1}=((19*(TR{i}(t-1,1)))+TR{i}(t,1))/20;
      end
    end
end

I tried this, but the answer provided becomes 0 for all cells.