Statistics for a restrospective study

I am looking for a freelancer to perform statistical analysis for my retrospective study. My sample size is 121 and I would like to use a significance level of 0.05 for my tests. This is a study of patients who underwent bariatric surgery for weight loss. I have collected data on a few parameters that could affect the weight losses that the patients experience after the surgery. I want to see if the presence or absence of these parameters really affects weight loss.

I am not sure which statistical tests I should use, so I am looking for advice from an experienced professional. Once I know the tests that are appropriate, I will need that analysis done for me in a timely manner. I expect the results to be accurate and reliable, so I expect you to have a strong understanding of the methods and approaches needed for this job. If you believe you can provide me with the quality of analysis I need, please submit a proposal for consideration. Thank you.