correlation

  1. G

    What is best method to calculate correlation for 2 nominal variables?

    Hello, I am analyzing data that looks at several nominal variables (e.g. employment status, race, gender, etc.) to determine if it plays a factor in the person's adherence to medication (also a nominal variable). What is the best way to do that? From what I've read on the forums and...
  2. E

    Need Help with Correlation

    Hi, I am trying to figure out the best way to calculate correlation with data I have for my business. Here is an example of what I the fields: Sale Amt - numeric Sold - yes or no State - lists 1 of 50 states Industry - lists the industry of the buyer Lead Source - lists where the lead...
  3. B

    WTI price vs. Drilling Cost Index

    Hi Folks, I have 2 datasets, each recorded on a monthly basis. The first dataset is the average monthly oil price. The second is a price index for drilling cost. I was to calculate what % change in drilling cost to expect with a 1% change in oil price. The data set spans 8 years and you see a...
  4. A

    Unsure what SPSS test to run--comparing means.

    I am a SPSS beginner. My hypothesis is "Women who score high on self-esteem will score low on upward comparison than women who score high on upward comparison." I have all the data cleaned up and the total scores found for all my scales, I am just unsure what SPSS analysis I should run. Is it...
  5. B

    Why one-tailed sig. in SPSS Regression Correlation

    Given that a two-tailed significance test is usually preferred unless one has a hypothesis about the direction of the relationship, why in the Regression descriptives output does SPSS default to a one-tailed test for the correlations, without any way I can find to change it to two-tailed?
  6. L

    Finding correlation for penalized regression in R

    I need to use the penalized models (lasso, ridge) for linear regression. In R, I use the "penalized" package. The output is a penfit object. If I want to find the in-sample and predictive correlation, how can I do that in R? Converting the penfit oject to glm maybe a good idea,but I don't...
  7. M

    bootstrapping correlations Spearman vs. Pearson

    I would like to calculate simple correlations. Since my sample size is quite small and data are not normally distributed I thought about Spearman’s correlations. Then I read about bootstrapping as a distribution free method and, considering my small sample size, I decided to use it with...
  8. R

    PCA (correlation) Biplot - correlation and angles

    Hi, I have a question regarding a PCA correlation Biplot. As far as I understand, angles between lines are (approx.) correlations between corresponding variables. Especially, if the angle is about 90° between two lines, these two variables are uncorrelated. But how does the plot look like if...
  9. I

    Correcting for regression to the mean in mixed effects model of longitudinal data?

    Hey everyone, I know you can correct for regression to the mean for two time points, in a before and after scenario. But does anyone know how to do this when there are more than two time points, let's say there are about 10 points in a time series. I was hoping to model the longitudinal data...
  10. D

    Generating random data from correlations

    Say I have a list of personality traits: courage, materialism, compassion and so on. I interview some people and assign a rating from -10 to +10 to each trait for each person, then I find the correlation between each pair of traits. Now I want to create a "random person" by assigning a value...
  11. C

    Can you perform an ANOVA on r-values (correlation values)?

    Hi all: This may be a simple question but... I'm doing neuroimaging research and long story short, I am doing what is essentially a correlational analysis wherein my output is a brain's-worth of r-values (so like 15000 voxels worth of r-values). In this particular study I had 3 groups and I...
  12. C

    Difference between two lmer model .

    Can you please explain where is the difference between the following two models : fm1 <- lmer(Reaction ~ Days + (Days | Subject), sleepstudy) fm2 <- lmer(Reaction ~ Days + (1|Subject) + (0+Days|Subject), sleepstudy) I noticed there is some discrepency in the estimate for random effect...
  13. L

    Types of interactions

    Hi, I am stuggling to find the right words for the statistical terms I would like to look up. Hope, you can help :-) I am looking at a higher order construct (organizational climate), which manifests in eight dimensions. I am interested in elaborating how these dimensions interact and what...
  14. K

    confidence intervals for correlations on AMOS or SPSS

    Hello, I was wondering how to calculate confidence intervals for a correlation coefficient on Amos or SPSS. I've been trying to do it on SPSS by standardizing my data, but i've been told the estimate is not fully accurate. When i try to do it on Amos, i get the correlation coefficient but no...
  15. A

    Help with interpretation

    Hi All, Here is what i need help with. I am working with small sample size and this is the result so far. X and Y are not correlated ; however, when I place X in a stepwise multiple regression predicting Y, alongside three (A, B, C) other (related) variables, X and two other variables (A...
  16. K

    Statistical test for comparing means of correlation coefficients

    Suppose that I have two lists of correlation coefficients such as A = [0.5,0.3,0.25,0.3,-0.1] and B = [0.8,0.7,0.75,0.8,0.8]. The correlation coefficients in A are independent to B. Now, I want to test the null hypothesis, that the means of both lists are equal. I am familiar with how to...
  17. M

    Statistically compare 2 3D structures

    G’day Statistics Forum I’m having a little bit of trouble with the statistical analysis segment of my honors thesis proposal and was hoping one of you helpful folk might be able to offer some insight. I believe this sounds more complex than it actually is, so bear with me cause I am really...
  18. S

    Predictive model for Turnover - Correlation or Survival Analysis

    Question 1 - I a working on developing a model to predict employee turnover. The variables that I have are age, tenure, job satisfaction, role clarity etc. Through research papers I have found the correlation coefficient for these variables but I am not sure on how to develop a model around it...
  19. E

    How to do Kendall test with ordinal data

    Hi, I have the following profitability data: 1) Rankings of profitability for customers: 1, 2. ... 15 2) Categories of same customers, grouped after profitability (from 1 to 5): 5, 5, 5, 3, 4, 5, .... 5, 4 (15 in total) I have troubles finding the Kendall Tau...
  20. M

    software speed

    Not homework BTW ... I want to measure the processing time (performance) of some software under a set of fixed conditions. I have a means to log the start and stop of the processing. The only possible factors are some uncontrollable (noise) factors, e.g., the CPU and memory usage. Then there is...