r=[2 2.3 2.5 2.7 3 3.2 3.5 3.8 4];C=[72 150 195 280 380 510 735 980 1250];
General model Power1:
f(x) = a*x^b
Coefficients (with 95% confidence bounds):
a = 5.182 (3.918, 6.446)
b = 3.947 (3.761, 4.133)
Goodness of fit:
SSE: 1871
R-square: 0.9986
Adjusted R-square: 0.9984
RMSE: 16.35