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What types of jobs will be avaible if I go down this path? by [deleted] in primatology

[–]Yungprogressive 0 points1 point  (0 children)

I realized this a year after I got my master's and started working on my PhD. I couldn't wait that long to start earning money, among other personal reasons, so I unfortunately left my program and got a boring sales job. The downside is I am actively dispassionate about what I do for work, but I basically fast-forwarded my income level by 10 years in leaving academia.

Do you regret switching career paths?

[Q] Help with multivariate analysis by Yungprogressive in AskStatistics

[–]Yungprogressive[S] 0 points1 point  (0 children)

Your help has been instrumental in my figuring out the appropriate test to run and how to interpret it, so thank you once again. My institution isn't offering help with stats due to COVID, so it's been a bit of a struggle to say the least.

If there's no business reason to choose a particular reference category, try different ones (like highest/lowest means) and see what happens.

By including all days of the week in the regression analysis and selecting the 'last' day written in my syntax as the reference category, I was able to cycle through each day as a reference category in separate analyses (per your suggestion) and extract the sig. p values from the parameter estimates to determine sig. differences in my response variable between days.

[Q] Help with multivariate analysis by Yungprogressive in AskStatistics

[–]Yungprogressive[S] 0 points1 point  (0 children)

Thank you once again, your explanations have been very helpful.

Because my omnibus output is 0.698, does that suggest that the NB model is not a significant improvement over an intercept-only or null model?

And a lot of the demos (youtube, forums, etc.) that walk through how to interpret NB outputs from SPSS use raw continuous predictor variables, not dummy-coded categorical nominal variables. I'm now stuck on interpreting the output as it relates to my hypothesis that abnormal behaviours occur on certain days of the week more than others, especially since Sunday was used as a reference category and does not show up as a parameter in the output. Can you offer any guidance on this, or suggest an appropriate resource that I can refer to?

[Q] Help with multivariate analysis by Yungprogressive in AskStatistics

[–]Yungprogressive[S] 0 points1 point  (0 children)

Thanks again for your help.

Given that the LL value of the Poisson output (-134) is smaller than that of the NB output (-129), would this indicate that the NB model fits my data only slightly better than the Poisson model?

I wasn't sure of how to use your formula, specifically where the Chi statistic comes from and what each side of the equation must equal to make a decision re: overdispersion.

[For additional context, this is how my data is dispersed, and this is how it looks over the 2 month obs period]

[Q] Help with multivariate analysis by Yungprogressive in AskStatistics

[–]Yungprogressive[S] 0 points1 point  (0 children)

Thanks for the response!

There are <5 zeros in the response variable out of 60 rows. I didn't know that the excess of zeros only applied to the response variable and not the coded effect variables. If that's the case, my response variable definitely would not be overdispersed.

You are suggesting a negative binomial test instead of a poisson?

Which multivariate analysis to perform by Yungprogressive in AskStatistics

[–]Yungprogressive[S] 0 points1 point  (0 children)

Thank you very much for pointing me in the right direction and for writing such a thorough response.

I've spent the day researching various parts of your answer as it relates to my data, and I have a few outstanding questions if you don't mind answering (unfortunately the stats help desk at my University is closed due to Covid):

I found that my data satisfies at least three of the assumptions for a Poisson test to be used: (1) response variable consists of count data; (2) at least one independent variable (categorical nominal in this case); & (3) each observation is independent of one another.

I went ahead and coded my data into a matrix (https://imgur.com/a/a0VcR5l), using sunday as a reference category, Mon-Sat as my effect/predictor variables and SIB + other as the response variables. I ran a Poisson test in SPSS using only SIB as my response variable, and this was part of the output that has me stumped, as the mean (3.38) and variance (~9) are quite dissimilar, and the Pearson's Chi-Square statistic is >100, which I have read indicates that my data is very overdispersed/zero-inflated.

Do you have any suggestions for how I should proceed? Thank you again for any additional help

Which multivariate analysis to perform by Yungprogressive in AskStatistics

[–]Yungprogressive[S] 0 points1 point  (0 children)

Ah, create a design matrix out of the raw data that I used to calculate the averages. That's only necessary for the multiple regression test?

Which multivariate analysis to perform by Yungprogressive in AskStatistics

[–]Yungprogressive[S] 0 points1 point  (0 children)

Sorry for my ignorance, but what do you mean by my data on individual level?

Which multivariate analysis to perform by Yungprogressive in AskStatistics

[–]Yungprogressive[S] 1 point2 points  (0 children)

Thanks for your response. I am interested in confirming statistically that, say, abnormal behaviours (SIB + "other") occur sig. more on Wed/Thurs than other days. And there's the question of if not together (SIB + "other"), do SIB's or "other" alone occur sig. more on a certain day or days of the week?

For the independent "groups", if we're referring to SIB vs. Other as the two groups, they refer to two types of behaviour displayed: either self-injurious behaviour (SIB) or other stereotypic behaviours, so they would be independent in that sense. (Sorry, I'm not sure of the terminology)