correlation

Hello everyone! I am hoping someone could offer me some wisdom and a few R tricks. I was lucky enough to get a pretty interesting data set for a study that I am doing. There is approximately 5000+ rows of data spanning 5 years for 100 different sales people. The data is structured per...

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<=...

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...

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...

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...

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...

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...

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...

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?

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...