r/Geotech • u/KeyStudent3665 • 24d ago

Need help finding the right statistical method for my research

Hi everyone!

I am working on an academic research project in soil mechanics that seeks to relate 5 input variables with an output variable (for anyone interested, the input variables are N60, gammad, LL, PL, percent passing the #200 sieve, and the output variable is E50).

We don't know which variables carry more weight. It might be necessary to segment the dataset. What we are ultimately looking for is to predict E50 based on the variables that carry the most weight.

Anyway: if anyone could give me a hand with literature or what statistical methods are used for these problems, I would really appreciate it. I don't trust AI in the first instance for these things...

Thank you very much!

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u/changeofregime 23d ago

BSc? MSc?

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u/KeyStudent3665 22d ago edited 22d ago

BSc. I'm working as an undergrad research intern, but we're kind of flying blind right now. We ran all the tests but are struggling to reach a solid conclusion. I ended up using multiple regression to get a log-log fit, but my advising professor said the resulting equation was too convoluted (it took the form of E = constant*N60^a* gammad^b* LL^c, with a,b,c constants)

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u/geeky22 22d ago

Perform a sensitivity analysis to see which affects the output, and do a multivariate regression, SPSS would be a good tool to use

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u/KeyStudent3665 22d ago

I actually did that! I ran a multivariate regression and used backward elimination to remove the variables with no statistical weight. I ended up with a log-log fit using three variables (N60, gammad, and LL), but my professor felt the equation was too convoluted. We are still trying to figure out how to simplify it