correlation

  1. K

    Correlation betweeen k binomial variables

    Hello, This is my first post as a new member, so hope I'm posting this in the right place... I need a general formula to calculate the minimum sample size N required to determine whether k binomial variables are somehow correlated (either positively or negatively) at significance level p<=...
  2. F

    Created a function that works fine but when asked to operate on its output it fails

    Hello, I have an assignment that requires me to create a function that calculates the correlations between two columns of 332 csv files based on my input. In short, what it does is find correlations between two columns of only the files that have either the same or more of complete cases as...
  3. S

    What method for this problem? [Correlation / Correspondence]

    Hi, I have a data set like the following with some categorical/nominal values (like Gender and Age Group) and a ratio scaled value (DropOut, which is the week after registration in which a person dropped out of a program [so it's never zero or less, and it's not the calender week]): I want...
  4. 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...
  5. 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...
  6. 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...
  7. 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...
  8. 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?
  9. 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...
  10. 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...
  11. 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...
  12. 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...
  13. 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...
  14. 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...
  15. 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...
  16. 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...
  17. 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...
  18. 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...
  19. 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...
  20. 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...