# groups

1. ### How to decide on a cut-off score (groups) if the scale doesn't have one?

For my study, I'm using a scale (rating scale from 1-7) that doesn't have a predetermined cut-off score. However, in order to do the stats, I need to make 2 groups/categories with "high score" and "low score". How do I determine the point at which a participant is considered high vs. low...
2. ### Predicting outcome with multiple groups

Hi everyone, I'm currently working with 3 different groups (3 disease populations) and I would like to predict which of the three groups they fall into based on a measurement we did. I was thinking that it should be something like multinominal logistic regression but how can I then get a...
3. ### Comparing Groups in Ordinal Logistic Regression

Hi, I seem to have gotten a little confused about the possibility of comparing groups in ordinal logistic regression. Here is my issue: I gave people one of three framing conditions for the goal of a task, which varied in the wording of how the goal was presented. Then I let people perform...
4. ### SPSS Error messsage - Post hoc tests are not performed for GROUPNAME in split file \$b

Hi all I have looked around but yet to find a helpful answer So I have two variables one containing a variety of species crosses (nominal)and the other variable containing the number of eggs produced (numeric) (see below) Between-Subjects Factors Value Label N Partnered species...
5. ### When to use Bonferroni

I am working with a mark-all-that-apply survey question that has 8 categorical response options. I am comparing responses statistically between two groups (dependent variables). 1. Are Bonferroni corrections supposed to be made only when you are comparing multiple groups, or does the number...
6. ### Hierarchical Cluster Analyis: Working with Groups

Hello everybody! I am not sure if you provide me an answer to my questions, but I am pretty desperate and would be glad of any help I can get! I am conducting a study in which I applied first Factor Analysis (for a question that was asked with Likert Scale, regarding characteristics of a...
7. ### Change within groups and differences between groups

Hi All, I have a question that perhaps is basic for most of you. I am hoping I can rely on your expertise to answer this question. I am trying to study the effectiveness of an intervention. All participants receive the intervention. Upon analyzing the demographics of the participants I...
8. ### Fisher test or interaction terms to determine if 2 groups are different

Hi, I split my sample in 2 groups, participants with condition +M and participants without the condition -M. I calculated correlations and beta coeff( regression by group) so what is the better way to see if these 2 groups differ significantly? the Fischer test for correlations or...
9. ### Simple 4 group comparison of means problem

I'll start by saying that I'm a neuroscience PhD student and have searched a long time for a solution to this problem but I can't find one. If you just have time to give a rough idea or point in the right direction then I'm grateful for any help. I am measuring the frequency of the same...
10. ### planned comparison (post hoc) with fewer than 3 groups?

Say you've found that the IV "sex" has a significant effect on your DV, but you want to know the nature of that effect. If your IV were something like "gender identity", you could run post hoc tests in ANOVA, because you would have 4 groups. But "sex" only has 2 groups. To wit, SPSS will not...
11. ### Testing the significance of change between two groups

Hi all, I was hoping for some advice on how to test the change between two groups. First of all, my groups are relatively large (n=100-150). For each member of the two groups I have the following: I have observed 'x' many of something in group one, and have extrapolated this to expect 'y'...
12. ### Computing an overall measure of variance for multiple groups?

Hello everyone, I am hoping someone can point me in the right direction regarding a variance question that I've encountered. I have greatly simplified my question/problem into the following example. I am trying to compare the variability in the manufacturing method of two facilities, say A...
13. ### Random Resampling from Nest Data

First off, thanks for your help if you have any comments, and I apologize if there is a post about this somewhere (I was unable to find one). So, here is my problem. I need to randomly draw samples from my dataset of grouped data. I have observations in separate rows. Each participant belongs...
14. ### Logistic regression analysis

Hi! I would like to do a logistic regression analysis on a binominal dependent variable. I have 7 explanatory variables but I'm worried about the distribution of the dependent variable. There are 3000 individuals in the population, but only 250 with positive outcomes. What are the main...
15. ### Factor scores to classify groups?

Hi there, I have carried out a principal component analysis and I would like to use the factor scores to classify 5 groups of respondents. What should I do? A discriminant function analysis? Thank you :)