Trouble setting up NonlinearModelFit with multiple independent variables

Questions
,
1

I am trying to fit a nonlinear model to some data with multiple independent variables.

My data is imported from .csv file and has the form of “H, P, n, MR” as collumns. My model is Beta*(H^0.75 + n*P^0.75), where I am trying to fit Beta (a normalization constant)

I tried the following, with no luck.

nlm1 = NonlinearModelFit[data, B * (HostMass^0.75 + NumPar*ParMass^0.75), {B}]

Any sugestions on how to properly use the syntax?

Thanks,
Blake Stevison

2

If you type your code into Mathematica, the first thing you’ll notice is that there is a red arrow after {B}. This indicates that there is an argument missing to this function. NonlinearModelFit takes four arguments.

  • The data in the appropiate format
  • The equation for the statistical model
  • The parameters whose values you are trying to estimate
  • The exogenous (independant) variables in the model