linear fit with fitlm or regress

10 次查看（过去 30 天）
Andreas Grøvan Aspaas
评论： Andreas Grøvan Aspaas 2019-5-15
Hi
I have a data set of three variables. I want to use the equation y = a + b*temp + c*temp* sigma. When i write this like y~temp+(sigma*temp) in fitlm, I get 4 terms, Intercept, temp, sigma and temp:sigma.
My question is if sigma is the slope c and temp:sigma is temp*sigma for the c? I think this is correct, but I have not been able to figure out how the equation would look like based on the input arguments. The displayed "Linear regression model" is y ~1 + t*sigma
Thanks a lot!

请先登录，再回答此问题。

采纳的回答

Jeff Miller
Jeff Miller 2019-5-14
Your three variables are y, temp, and sigma? If I understand the model you want to fit, you might get a cleaner picture if you form a new variable:
prod = temp.*sigma;
and then use
y~temp+prod
  5 个评论
显示 3更早的评论
Jeff Miller
Jeff Miller 2019-5-14
Sorry, I just don't understand what model you are trying to fit. You say you are trying to get
y = (a0+b0*T) + (c0*sigma+d0*T)
but that does not look like a legitimate model to me as I said before.
Andreas Grøvan Aspaas
Andreas Grøvan Aspaas 2019-5-15
Ok. It might not work. I was just thinking that I should be able to make whatever formula I wanted if I told matlab to make it.
I think the prod method you proposed works though. I do not get c0 and d0, but I get them both combined if I am not wrong. And this is enough as I just need to know how significant it is. It would be better to have them separated, but as I am not able to I am going to just accept it.
Thanks a lot for taking the time!

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Gaussian Process Regression 的更多信息

标签

产品


版本

R2018b

Community Treasure Hunt

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

Start Hunting!

Translated by