MATLAB Answers

Linear and power fitting of original and transformed data not reproducible

2 views (last 30 days)
Xen
Xen on 30 Jan 2020
Commented: Vladimir Sovkov on 30 Jan 2020
I am fitting two variables that seem to have a power relationship (y=a*x^b). If I log-transform both variables, they should have a linear relationship (ln(y) = c*ln(x) + d. Notice that b=c and ln(a)=d. However, when I fit the power and linear equation to these, respectively, the estimated coefficients do not satisfy these relationships. Expectedly, R-square is also different. I tried changing the fit options and didn't manage to make the two fittings equivalent. Has anyone any idea why this happens?
PS. fitting in excel is satisfying these relationships and I get identical values
  3 Comments
Vladimir Sovkov
Vladimir Sovkov on 30 Jan 2020
The weights must be , however, it is better to check the documentation of the tool you are using.

Sign in to comment.

Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by