# Search results

1. ### Why are so many variables in my regression significant?

Having no idea of your context, I can point out that the estimate sizes are very small and perhaps insignificant in a business sense. A reason could be that you have a very large sample size so the model is picking up trivial effects.
2. ### Using the Crawford and Garthwaite (2002) modified t-test for the reverse purpose?

I didn't really understand this sentence. Why couldn't you just do a one-sample t-test?
3. ### Need help regarding project

Whenever you conduct a study, you typically conduct a sample size calculation if there is an inference you are going to test. At this part you have to have a small sample, meta-data on the population, or make an educated assumption on values of variability. So you likely need to pick one of...
4. ### Question in interpreting Effects Size - versus p - Very large data sets

@obh - agreed. I was just referring to the second (super saturated) model. I would image 13% would be useful.
5. ### Question in interpreting Effects Size - versus p - Very large data sets

Yes, so if I follow, your variables seem to explain a fraction of a percent of the variability in the outcome. Which I would imagine is near useless. In addition, in order to look at interaction terms you need to have solid suspicion/theory that they could exist. You can't just look at every...
6. ### You've asked 55 parents if they have more than one child. It turns out that 77 in 100 parents have more than one child. Compute the 99% confidence int

Is there a reason why you wouldn't treat this as a binary variable (>1 Y/N)?
7. ### Still having problems...Am I missing something obvious?

Sounds like a fun experiment. This seems like a basic study design that you could see in agriculture. I personally haven't done basic studies like this before, so won't be a great help. What kind of values did you see in your outcome? This may dictate if you are working with a Poisson or linear...
8. ### Election 2020

Yeah, we will see if he selects a female running mate to procure some more votes.
9. ### Binary logistic regression warning message model summary help!!

Yeah, with small samples or sparsity - Firth's is a simple and not too esoteric option.
10. ### Binary logistic regression warning message model summary help!!

It sounds like the model is failing to converge. Multiple things could be going on. The most common is complete separation, meaning that in one of the groups all members are in one of the outcome groups. You can check for this. Work arounds sometimes can be, changing the number of iterations...
11. ### t, Z and sigma again

Not the answer you are looking for, but you could do some simulations. Simulate a population, then draw samples from it without replacement and conduct ttests and z-tests on samples.
12. ### t, Z and sigma again

Good question - I never really think about using the z-test. I feel like they teach it, but then given my field I have never used it. Also, I feel like both the t- and z- get taught, but in real life most settings require a multivariable setting. I also agree, that I don't grasp the setting...
13. ### Homogeneity requirements for Linear regression

Yeah, you all say this, but I think it should still be looked at to make sure something crazy extreme isn't going on. Visualization are so important. It could also reveal that say some outcome values aren't present or if values are bounded. Or help find erroneous outliers. It can't hurt to look...
14. ### Hayes Process V3.3 Model 89 in SPSS V25

I could see wanting to know the effects of each term, but that causal diagram has two subsequent moderated mediators. I question how someone would suspect that and if you need to address it, since the first would be conditionally independent of the outcome since the second one likely screens it...
15. ### Observational Study

Well you are going to have bias. Epidemiologists usually break issues into confounding, information bias (measurement error /misclassification), and selection bias. Drop out may results in selection bias if it is systematic.
16. ### What is this time series coding doing

:) I love it. You can't make this stuff up. Yeah, I thought this was what you were after. [] can be use to grab rows, columns, and datum. In this situation it tells the function which variables to use from the dataset. Columns are listed second when using [], so that is why it is [ , then...
17. ### Hayes Process V3.3 Model 89 in SPSS V25

See you haven't gotten much feedback. I am not really experience in mediation analysis, so remember that. When I opened the file I was not expect that causal diagram. Figured it would be a simple scenario. So you have two subsequent mediators and posit moderation across the board. I guess that...
18. ### relationship between correlation and average

There are other sources of happiness that may need to be controlled for in order to extrapolate results across populations, correct? PS, welcome to the forum and try not to use "help" as the title of the post. Provide at least an attempt to describe.
19. ### Observational Study

Observational studies arent that bad. The ideal setting is when you can intervene on a variable and have temporal collection of data. Of note, even small randomized studies can have residual confounding. Though when it is present day anc unethitical to randomize r some treatments, observational...
20. ### Observational Study

So their outcome was in-hospital mortality (which could include other things - probably not many not relate to the disease course). They said to shift the lower bound of the hazard ratio and nullify the result it would require not accounting for a unknown/undocumented confounder about the size...