1. S

    Correlation and ROC analysis with repeated measures data

    Hi all, I have a hypothetical study where participants are taking drug X per standard of care. I have 3 different timepoints (baseline, therapy, post-therapy follow-ups) at which participants have biomarker sampling and echocardiograms performed. Exploratory objective: efficacy; Exploratory...
  2. spoikayi

    Correlation to ratio of two variables from individual correlation.

    I am trying to estimate the correlation between three parameters, from some know correlations between some of them. I know the correlation of two variables Corr(k,1/a), Corr(k,1/(a+b)). How can I calculate Corr(k, (1/(1-(b/a)))? Also, if the two known correlations [Corr(k,1/a)...
  3. N

    Spearman Rank + Quadratic Regression (spps) HELP! x

    Hi, I'm trying to find out if there is a significant correlation between salinity and no. of Bivalves found on a shore. I did a Spearman Rank and this was my result: "There was a statistically significant correlation between Salinity and the number of Bivalvia individuals (Spearman Rank...
  4. C

    Association between non-normal continuous variable and dichotomous variable

    Hello, I'm trying to examine the association between a non-normally distributed continuous variable and a dichotomous variable: yes/no. At first, I thought I should conduct point-biserial correlations but then I realised that in point-biserial correlations, the continuous variable needs to be...
  5. S

    Which correlation coefficient is best suited to dichotomous variables (and why do my results feel intutiteivly wrong)

    I have collected data that shows the days on which I fasted and if those days resulted in weight-loss. Null hypothesis: There is no statistically significant relationship between fasting and weight loss. Data Analysis: 1 The chart (see way below) is a visual representation of my data. The...
  6. A

    Correlation with unknown numbers

    I am looking at a data set that can correlate prior doses of drug A with the amount of time (in days) before developing infections after stopping drug A. We hypothesize that people with lower dose will have longer latency before developing infections. But we have a lot of people (especially...
  7. M


  8. K

    University project help (correlation)

    Hello dear stat-folk! I'm currently in the process of re-writing my project due to a failed exam in it. In this regard i'm having trouble figuring out whether i can even use statistics (and how) to describe a theory i have towards a possible correlation. In this part of the project i am...
  9. P

    Advice on which analysis to use for count data...

    I am looking to examine whether one variable (counts of social interactions) is associated with another variable (counts of running activity). Both variables are simply frequency counts of behaviours which were counted at the same time during 40 hour-long observation periods across two weeks...
  10. M

    Comparing correlation coefficients

    Hello, I have a large sample of patients who have had a TIA, minor stroke or major stroke. I have been looking at correlations in each of these three groups. Is there a statistical test in SPSS (or elsewhere) that would allow me to compare the correlation coefficients between each of three...
  11. W

    panel data correlation

    Dear All I want to study the effect on ROA for a pharmacy that has an online pharmacy department compared to pharmacies that don't. This is my regression: Return on assets = b0 + b1*ln(total assets) + b2*ln(firmage) + b3*leverage + b4*current ratio + b5*dummy online pharmacy + b6*dummy online...
  12. S

    Can a ratio of performance be used to measure dependence and assign weights in a weighted average?

    With only a modest grasp of inferential stats and maths in general, I've been wondering how one might derive the weights for a weighted average from a variable that isn't as straightforward as a frequency score. Consider the following scenario. Let's say I have measurements of effectiveness for...
  13. A

    Test for Multicollinearity

    Hello Talk Stats Forum! I am working on building a Predictive Model using the binary logistic regression and LASSO logistic regression. In order to apply these models on some real data set I am using R software. Before performing such a model I am testing for multicollinearity and will remove...
  14. D


    Hello. I have 99 patients divided into subgroups according to the following variables: 1- Their syntax score (which measures how severe the obstruction in coronary arteries is). Values of this variable are between 10.2 and 41 and are classified into three levels, first 1-22, second 23 - 32...
  15. T

    Correlation analysis: spearman or pearson

    Hi, We are conducting research on the relationship between self esteem and aggression. We have aggression scores and self esteem scores and we want to find out if there is a significant difference in the relationship by gender. We have ran a pearson's correlation for the relationship for the...
  16. T

    Multi-correlations analysis

    Hi everyone, I’m recently struggling with a situation below, may anyone be kind enough to offer me a helping hand please. Student / mins of leisure time / page studided / marks in exam A / 50 / 100 / 90 B / 55 / 85 / 80 C / 60 / 80 / 70 Now for student D, he has 50 mins leisure time and...
  17. M

    Agreement between 2 measurement methods

    Hi, I am trying to find the agreement between 2 methods that estimate the size of a knee (CT and MRI). n brief, each knee can get a size from 1-7 where 1 represents the smallest size available and 7 represents the biggest size available. In my study, I have 100 different knees that were...
  18. C

    Correlation of two variables through others

    Hi, I have two data sets. In both sets there are 3 of the same variables (density, MOE and frequency). In addition to that, each set has one more variable (tension strength and bending strength). Since i can not measure both strengths on one piece, I would like to estimate the correlation (or...
  19. M

    Relationship between a variable with categories and a variable with numbers?

    In SPSS, is there a way to find out if there is a siginificant relationship between symptoms (on a scale from 0-3, with 3 = the worst) and hospital stay ("yes" or "no") are related?
  20. M

    Can I use chi-square for one nominal and one ordinal variable?

    Can I use chi-square test of independence if one variable is nominal and the other is ordinal, or do both have to be nominal?