cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 
JMP is taking Discovery online, April 16 and 18. Register today and join us for interactive sessions featuring popular presentation topics, networking, and discussions with the experts.
Choose Language Hide Translation Bar
Jonkandonkan
Level II

Odds ratio for a simple distribution

Hi

I'm looking at the distribution of individuals participating in different events. Here, I'm looking at "thirds" (i.e., first, second, third part of the year, not sure "Tertial" is the correct word in english), could also be quarters, Q1-Q4.

When doing a distribution plot, I can also test the probability/ do a chi-2 test, and thereafter get the likelihood ratio, and its confidence intervals. However, is there a easy way of calculating the Odds Ratio for this? That is, the odds that you are placed (in this case, born) in T1 instead of T3. I've tried to look around and one can doo Odds ratios under logistic regression models but that seems inappropiate for this case?

Skärmklipp.PNG

15 REPLIES 15
Jonkandonkan
Level II

Re: Odds ratio for a simple distribution

Thanks for you patience!

Hm, I already have the likelihood ratios from previous analysis. However, in this format I could automatically calculate ORs using Formulas, (but what about 95% CI for OR?)

Also, for me these doesn't make sense:
JMP4.PNG
T3 can't have the highest probability, with fewest individuals? 

Re: Odds ratio for a simple distribution

The model is for the marginal probability. Is it true that the group T3 is always smaller? You could use Tables > Summary to get the Sum for T1-T3 overall. Those sums are where the probabilities come from. (You did not enter any covariates so the probabilities are not estimated for each grouping.)

Jonkandonkan
Level II

Re: Odds ratio for a simple distribution

Well, almost always. But in that dataset, as you can see T3 has the fewest but highest probability. 

 

Now, with Age as Covariate (As a model effect?) it says: Failed: Cannot Decrease Objective Function, but can proceed and now it makes some sense:


JMP5.PNG

Jonkandonkan
Level II

Re: Odds ratio for a simple distribution

Then, using the formula, I get the OR, which seems correct. Then I just need to come up with the formula for calculating 95% CI using this set... Anyone?

JMP6.PNGJMP7.PNG

Re: Odds ratio for a simple distribution

There is nothing wrong with your OR calculation as far as I know but I have never used them with the marginal probabilities so I do not know how to estimate the OR with a confidence interval in your case.

 

You might send your request JMP Technical Support (support@jmp.com).

 

You can also use another software with this capability. There are many on-line calculators although the ones that I found for you did not apply to this case. If there is an R package, then you can write a short script to make JMP work with R to get the results for you.

 

I'm sorry that we do not have a simple and easy, ready-made solution for you.

Jonkandonkan
Level II

Re: Odds ratio for a simple distribution

Thanks.

Yea, didn't find any online calculator suitable for this approach. 

 

Think I will try SPSS (against my will) for just this one.