If you have Excel, have you explored using it? I know that I have done exactly that myself, but I can't remember whether it required an "add in" statistical analysis pack to do the nonlinear modeling (and even it does, there are a number of those available online for free on the web).

Hi, SPSS can carry out non linear curve regression with the name "curve estimation" here is a hopefully useful video for doing these analyses:

https://www.youtube.com/watch?v=kh_M5_MHWA4

Hi, SPSS can carry out non linear curve regression with the name "curve estimation" here is link for a hopefully useful video for doing these analyses:

https://www.youtube.com/watch?v=kh_M5_MHWA4

Hello Prashanth, 

Have you tried to utilization of softwware Web Enabled Statistical Software for Analysis, This is freely available at www.wessa.net and it is also FREELY available

Try it. You really enjoy using its prediction and representation power

Dear All, Thanks for the kind information.

Dear Prashanth Gopala Krishna,

You can do it using Excel without any special/external add-in. You just need the Solver Add-in that comes with excel.

If you're willing to send and example set of data I'll share an excel workbook to perform the curve fitting (non-linear regression) as well as the corresponding chart.

BR Luis

Often the nonlinear correlation to be fitted to data can be 'somehow' linearized, as a first stage. Linearized correlation and the corresponding linearized plot are often quite convenient to qualitatively evidentiate scattering around the trendline and to emphasize major effects and the physical meaning of the correlation parameters. Estimates of the parameters derived by least squares after the linearized correlation (modified from a former nonlinear correlation) can possibly be refined by iterative nonlinear least-squares regression; to find unbiased least-squares estimates for the original correlation. It may be advisable to compare both the linearized and the nonlinear correlations.

The following RG discussions seemingly can be found of some interest, concerning to your query:

https://www.researchgate.net/post/How_can_I_find_an_specific_equation_that_can_describe_the_relationship_between_X_and_Y_in_the_attached_file

https://www.researchgate.net/post/How_to_perform_nonlinear_data_fitting_for_a_given_equation_and_data

https://www.researchgate.net/post/How_to_generate_a_non_linear_curve_fitting_function_with_multiple_variables_using_Origin

https://www.researchgate.net/post/How-can-I-fit-an-exponential-curve-of-the-form-y-AexpBx-C

https://www.researchgate.net/post/How_choose_determine_initial_values_of_parameters_in_curve_fitting

https://www.researchgate.net/post/How_to_fit_viscosity_data_using_Vogel-Tamman-Fulcher_VTF_equation

https://www.researchgate.net/post/How_to_estimate_initial_values_in_non_linear_models

https://www.researchgate.net/post/How_it_can_be_possible_to_fit_the_four-parameter_Fedlund_model_by_only_3_PSD_points

https://www.researchgate.net/post/How-to-evaluate-the-fitting-results-when-I-use-OriginPro-to-do-curve-fitting

Carlos Araújo Queiroz It has been about 6 years since Prashanth Gopala Krishna asked the question and thanked respondents for their answers. I think he kas moved on.