If I run this script i get a good fit, see image
N=10:10:60;
t1 = [3.5 6.5 10 12.5 15.5 19];
t2 = [3 6.5 10 13 16 20];
t3 = [3 7 10.5 13.5 17 20];
t4 = [4 7 10 13 16.5 20];
t5 = [3.5 7 11 14.5 18 20.5];
T = [t1;t2;t3;t4;t5];
m = mean(T);
[c] = polyfit(N,m,1);
f = c(1)*N + c(2);
plot(N,f,'g')
hold on
scatter(N,m,'b')
Best Answer