# correlation

1. ### Understanding correlations in order to test speed-accuracy trade-off in experiments

I understand that in experiments where the measures of interest are speed (reaction time) and accuracy, for an effect to be valid one needs to make sure there is not a speed-accuracy trade-off (SAT). Namely, as reaction time gets quicker for a condition, accuracy should also be better for that...
2. ### Help with Correlation

Hello! I need help for an issue i have. Let's assume that we have data of two variables (X and Y) for 14 different people. We can find the correlation between those two variables, for each one. In my case i find moderate correlation in some of them (which is also stat. significant), and for...
3. ### multinomial logistic regression

hi , i have two questions: 1)- is it adequate to run a multinomial logistic regression test using spss on two categorical variables to test the influence relationship, knowing that data is collected via likert scale items and then computed into 5 classes : example from 5 to 10: weak, from 15...
4. ### Can I use a pearson correlation with repeated measures?

I have measured 5 different behavioural responses of birds to birdsong playbacks from a speaker (e.g. how long they took to sing back to the playback song, how long they took to approach the speaker etc..). Each bird was measured twice for each behaviour. Now I would like to know if...
5. ### Spearman's rho or no? is one of my datasets non-monotonic?

Hi, I'm dyslexic with limited stat education (and the internet is not helping thus far) and I'm having horrible trouble understanding what tests I can and cannot use for potentially non-monotonic data (brain, meet brick wall...). This is for my dissertation (social sciences), and I'm questioning...
6. ### Beginner questions: Clinical trial

Hi there! I am a medical student working on my PhD, and I am analyzing some data for a meeting. Since we don't learn much about statistics (at least not here in Germany :D), I have some beginner questions and I would be extremely happy if you could help me. The first question is the most...
7. ### Correlation matrix with significance

Does anyone have a ready-made function or know a way to produce a correlation matrix with asterisks marking significance levels in R?
8. ### Regression Analysis

Hello, It would be great if somebody can help me with this: Is it correct to conduct factor analysis on data source (A) and then run a simple regression analysis with derived factor from factor analysis as independent variable and a item from the same data source (A) as dependent variable...
9. ### Choosing appropriate statistics (please)

Hi, I have an issue (mostly being clueless and trying to achieve more than I can), I am writing a page in Ruby on Rails for which I need to calculate the probability of two events being correlated (basically the likelihood of a trigger being the cause of a symptom, or since correlation doesn't...
10. ### Generating confidence intervals for both height and weight with the same sample?

Given that height and weight tend to be correlated, would it be okay for me to use a single simple random sample of people to create confidence intervals for both their height and their weight?

12. ### Interpreting correlation split file data

Hello, I ran a split file correlation with the race as a group. I am not sure how to interpret a section of this chart, particularly the last section which is labeled "9.00." Is that a summary? What does that mean? Thank you,
13. ### Permutation correlation with one non-normal variable

Hi, I am trying to assess the relationship between a relatively normally distributed variable (brain volume) and a strongly right-skewed behavioral measures, which cannot be transformed to normality. I assume a linear relationship between the two variables. My plan is to calculate the...
14. ### Joint Density Function From Given Correlation

How do I find joint density function from a given correlation?
15. ### Power Analysis

Hi there, I am currently writing a statistics report which has to cover 2 questions: Firstly, what the correlation is between two different test scores of 30 participants. Secondly, what the power of the study is. I am really struggling to grasp what the pro's of doing a post-hoc power...
16. ### nominal (yes/no) and distance. What test to use to proof correlation?

Hi all, My boss has a list that shows the interest of people for a new venue (interest? Answer: yes or no) and the distance to that possible venue. He asked me to show if there is any correlation between the two of them.. Although I searched and searched, I find it hard to decide which test...
17. ### Question on the merits of mediation analysis Vs another analysis (described within)

Hello, I have a dataset involving an intervention (placebo versus real) - denoted as X, an outcome (Y), and a physiological variable (M) that I hypothesised would mediate the effect of X on Y. I have shown that X did not significantly affect Y (as assessed using simple linear regression), but...
18. ### Find Correlations

Let's say I have some samples, that I gathered per second, like these Number km Benzine Speed Weight 1 10 100 80 100 2 20 90 100 120 3 30 80 80 110 with thousand of samples and more than twenty features (like speed and...
19. ### Multivariate correlation coefficient?

Is there a simple definition (formula) for a multivariate correlation coefficient between k binomial variables, assuming that each variable is positive with the same probability/frequency f? What does the CDF for this multivariate binomial distribution look like, and how does it depend on the...
20. ### Correlation based on multiple measures / observations

Hello everyone! I am hoping someone could offer me some wisdom and a few R tricks. I was lucky enough to get a pretty interesting data set for a study that I am doing. There is approximately 5000+ rows of data spanning 5 years for 100 different sales people. The data is structured per...