Finding coefficients for hyperelastic fits

Hi,

I have some tensile test data for a hyperelastic material. I have already found the co-efficients for 5 term Mooney-Rivlin fit using a FEA software, But if I had to do it using Matlab , how should I do it? I know I have to use the least-square method. I have no idea how to approach it. Any help is appreciated!

Thank you.