1. C

    Dealing with linear dependent variables

    I have a large dataset with many subject each with responses from a consecutive year going back 10 years (ie 100,000 persons per year (not necessarily 10 data points per person as they may not have been part of the study in prior years) dating back 10 years). I have data on each specific...
  2. K

    1 level of nominal IV correlate to Interval DV - how to do this?

    1 level of nominal IV correlate to Interval DV - how to do this in SPSS? I have 1 categorical Iv which has 4levels - and 1 dv which is interval scores The 4 levels of the Iv are 4likert scale responses - from "not at all"=0 to "always" =3 I want to find out if there is a relationship...
  3. C

    Sample size calculation for multiple regression

    Hi all! I am struggling with sample size calculations at the minute. I have looked everywhere but all I get is formulas. I have downloaded MedCalc which gives me a number of participants I need per correlation. My supervisor keeps confusing me because she says that it is a different number...
  4. D

    Do you think there is any correlation between this two variables?

    Do you think there is any correlation between these two variables? scatterplot: data with software R: variable sd.prices:
  5. R

    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...
  6. C

    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...
  7. G

    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...
  8. T

    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.
  9. I

    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...
  10. S

    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...
  11. L

    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!
  12. B

    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...
  13. C

    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)...
  14. H

    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...
  15. J

    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...
  16. B

    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...
  17. B

    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...
  18. J

    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...
  19. N

    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...
  20. T

    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