# correlation

1. ### Dealing with data where the values of variable Y depend on values of variable X

Hi there, I've been doing some undergrad research and am confused about how to handle some of my data (and my professor doesn't know much about stats...:( ) Basically, I'm looking at the durations of two behaviours in animals, behaviour X and behaviour Y. Behaviour Y occurs while the animal...
2. ### Cross-lagged panel size: sample size of 48

I have performed a cross-lagged correlational study with 2 variables and 2 waves. My sample size is 48 subjects. Is it possible to perform it with such a small sample? If not, what would be the options? Could I discuss results as having small power, or is it just not possible to perform this...
3. ### Positive correlations to dependent variable, but negative coefficients

First of all, sorry for the huge pictures, but I'm in desperate need of some input and help on the results following a study. I'm trying to interpret the results from my study, but I can't quite figure out what causes some of the positive correlations to turn into negative coefficients in the...
4. ### Parametric or non-parametric test?

Hi there, thanks in advance for any help you can give. I need to perform a correlation test between a parametric data set and a non-parametric data set: should I use a parametric test (Pearson) or a non-parametric test (Spearman's rho)? I'll be performing the analysis on SPSS.
5. ### How to interpret Spearman's correlation between Likert-scale questions?

Hi there! I have a question regarding the correlation of different statements. I would appreciate any help! How can I interpret this correlation? For example, I have 7 statements within one block (5-point Likert-scale) and respondents have to choose between whether they totally agree, agree...
6. ### Correlation Hypotheses (Pearsons) - Is a Null Hypothesis necessary?!

Hi :) I'm quite confused on whether it is possible predicting 3 positive correlations? Or is it necessary that there should be a null? For instance, these are my hypotheses below: H1: There will be a significant positive relationship between the Mean Reaction Time on the Emotional Stroop...
7. ### Linear regression after multiple regression

Please excuse my stupidity - would it make sense to conduct linear regression on the predictor variables remaining after backwards elimination in multiple regression? Any help appreciated!
8. ### Correlation Across Time Help?

Hi I'm a bit lost as to how to calculate the correlation between two groups of numbers across time. I'd like to see if one group, taken from the start of the time frame, has a significant difference or similarity to another group, which represents the remainder of the time. This may be a...
9. ### Comparing one rater with a group of raters

Hi all, I'm working through a research project, and am looking for advice. Students were asked to work through a simulated clinical scenario and were rated in real-time using a checklist. In addition, each scenario was videotaped and rated by 3 different raters (using the same checklist)...
10. ### Which Statistical Test to Use?

I am doing a research project in which I have collected variables on two separate groups. One group uses a self testing laboratory machine which I have labeled as "patient self testers" (PST). The other group does not use the self testing machine, "non-patient self testers" (non-PST). The intent...
11. ### Correlation interpretation: when to use "is related"?

If the selling of ice cream was found correlated (0.4-0.6) to the temperature, can we conclude that ice cream selling "is related" to the temperature? Or we can just say that there is a relationship? By using is related, do you imply cause and effect relationship? Can we also say that other...
12. ### In need of help with regression

Decomposing a regression coefficient - Desperate for help Hi, I apologize in advance if this is a very stupid question but I cannot for the life of me figure out how to do this. I want to regress the return of one asset onto another so as to obtain the correlation between the two, but I...
13. ### About Correlations between Mathematically Dependent Variables: Best Practice?

Summary / Basic question: How do I correct for a logical (/mathematical) dependency between two variables when I want to compute the correlation between these two variables? Specific Issue: Analysis Goal: To assess whether or not medical facilities favor some Procedure X more or less as a...
14. ### What is a anti-image correlation matrix?

Hello, I am currently doing an homework on Factor Analysis and PCA in SPSS and I have to present the Anti-image matrix and explain what it is. However, after having searched on google, all I found was this : The anti-image of the correlation matrix is the negative of the partial correlations...
15. ### Correlation to determine the best reference series for homogenization

Before asking this, I read similar questions, but none of them lead to satisfying answer for my specific interest. I want to homogenize a 64 years (1940-2003) climate time series of precipitation of Dominican Republic. For that, it is really important to select a reference series among a group...
16. ### find highest concentration of high value in a time interval

Hi I have this data set where I have timeStamp and response time. Using R how do I find the date time range which has the highest concentration of response time where respons time is greater than 2sec. I am new to R and stats. Thanks kumar
17. ### Test for correlation and differences in correlation - nominal and interval variables

Hi, I've got two types of variables - nominal (mode choice (e.g. car, bike, etc...) and interval (income range (e.g. 10,000-15,000, 15,001-20,000, etc...). I am trying to figure out the best test to see if the variables are correlated, and then I want to test to see if the correlation is...
18. ### What tests can I use?

Basically, I have to variables Carbon Monoxide (CO) and Black Smoke. I have to test whether black smoke influences the level of CO in the atmosphere at a specific site. I'm not particularly good at stats, can someone please let me know what tests I can do on Minitab to test correlation. So...
19. ### Scatterplot relationship issue.

Hi, the data below is just a sample of the data I am trying to enter into a scatterplot. The issue is that a previous correlation test shows a p value of 0.011, a clear relationship. However, when I took the averages of 196 entries of the data below, the scatterplot shows little...
20. ### Best Nonparametric test for nominal and continuos variables

Hello everybody. I'm looking for the best test to find an association between two variables: - a test score (continuous, ranging from 0 to 100); - a yes or no binary variable (like, for instance, being clever or not) Variables are not normally distributed and their relation is not...