# Recent content by bruin

1. ### sampling distributions - composed of permutations or combinations?

Below is an example of what I mean. After writing it out this way, I’m thinking that I answered my own question, and that the answer is: permutations vs combinations doesn’t matter insofar as it has no bearing on any probabilities derived from the sampling distribution. But I’m interested to...
2. ### sampling distributions - composed of permutations or combinations?

This seems like a very basic question, but I'm having a hard time answering it by googling. If a sampling distribution is composed of all the values of a given statistic derived from all possible samples of a given sample size, then does "all possible samples" refer to nPr or nCr? My guess is...
3. ### Mistake in a textbook: What proportion of studies make "wrong" conclusions?

I found the following statement in an undergraduate psychology textbook: The way I would read those sentences, they are clearly incorrect. Look at the last sentence: This sentence refers to 5% "of research conclusions." That sounds to me like mistaken research conclusions of all types --...
4. ### testing for significant differences among three proportions

When I said Chi-Square earlier, I was thinking of goodness of fit. I think I actually just need a Chi-Square test of independence with: Grouping variable: which Gathering (1, 2, or 3) Response variable: Dichotomous Age (over 30, under 30) Is that right?
5. ### testing for significant differences among three proportions

Yes. n1 = 20 n2 = 24 n3 = 30
6. ### testing for significant differences among three proportions

Hi, I know that three proportions seems like a Chi-Square problem, but I'm having trouble making my problem conform to a Chi-Square. Let's say I have three gatherings of people, and for each one I have measured the proportion of people that is over 30 years old; and I'm comfortable treating...