correlation

  1. B

    Analytical solution to correlation between two linear combinations of values

    Greetings, Suppose I have two linear combinations of values as follows: Y1 = B11*X1 + B12*X2 + B13*X3 Y2 = B21*X1 + B22*X2 + B23*X3 where X1 ~ N(0,1) and X2 ~N(0,1) and X3 ~N(0,1) Can corrY1,Y2 be derived analytically, that is, without me simulating numerous instances of Y1 and Y2 and doing...
  2. N

    Calculating correlation with unknown sample size

    Hello, friends. Here is the question that I would like answered. I have literally been sitting here for over an hour trying to find the solution on the web, and I am beyond frustrated (my broken arm doesn't help). What would be the correlation between the annual salary of males and females at...
  3. O

    Probability of Unconventional Food Item Alleviating Medical Problem Multiple Times

    For about 2 years, a medical problem has more or less repeated, as follows: The problem normally lasts approximately 3 weeks and then goes away for 3 or 4 days and then repeats. When eating a non-conventional food item, the problem goes away in approximately 2 days instead of 3 weeks...
  4. U

    Statistical Analysis help for thesis - Correlation, Probit, Tobit and Moderation

    Hello Talkstats users! I am writing here cause I need some guidance on my statistical analysis which has turned out far too complex for my basically begineer stats skills and my self research. Before I ask my specific, I will give some background to my work. The scope of my analysis is to...
  5. J

    Treating multiple observations per object

    My data consists of thousands of machine elements, their price, as well as technical and non-technical attributes. Most of the data is categorical The technical data contains information such as weight, dimensions, material. Each element (identified by unique code) has distinct technical...
  6. D

    Linear relationships between variables from different, but related data sets.

    I had a quick question. And I am sorry if it seems elementary, but I just have so much trouble with statistical analysis (I use R when I do it generally though). I am trying to test the correlation between the % coral cover at each of my study sites, and the % of coral in sediment collected...
  7. T

    correlation coefficient between 2 autocorrelated time series

    Hi I have 2 time series each 19 data points long which have a correlation coefficient of 0.5. Great! Problem. The time series are both display a large autocorrelation at 1 lag, small at 2 lag and zero at 3. How can I calculate the correlation coefficient taking this autocorrelation into...
  8. S

    Correlation coefficient for zero inflated count data

    Hi, I would like to ask what is the proper correlation coefficient to use for count data and for zero inflated count data. would Kendall tau do the job or would the data violate some assumptions of it?
  9. R

    comparing simulated and experimental data

    Hi All, I generated a time series data by simulation (each condition has been generated time condition1 condition2 condition3 .... condition50 0 70 70 70 70 20 67.3 69 70 56 30 67...
  10. M

    Meta-analysis: different information about relationships between two variables

    Hello everyone I need help with my meta-analysis. I have collected all the studies that I wish to include and would like to take Pearson's correlation as effect size. However, many of the studies do not report correlations, but rather path analysis or SEM coefficients or regression...
  11. S

    Correlation between two non stationary time series

    Hey everyone, I'm trying to figure out if there is significant correlation between two non stationary time series (e.g. temperature on a a given day and icecream sales). Could someone please propose a method. There are so many different methods i read about online im not sure which to go...
  12. R

    Logistic Regression Problem

    Hi! My collegue is developing a logistic regression to predict the probability of a customer taking up a particular credit card. Let's call the credit card the gold card, so his dependent variable on the left side is GoldCard = 0,1. On the right side of his equation he is also including a...
  13. I

    Puzzled by Correlation

    This is a real problem although I'm using a made-up statistic (# of apples) for this. Say I am interested in how many apples people eat in a year. This varies by many factors. First I look at the country difference (the US vs. Canada). From historical data of the average number of apples...
  14. R

    Multivariate repeated measures, binary and continuous

    Hello all. I am working with a data set of multivariate repeated measurements. Specifically, subjects performed an exercise they were taught up to three times each and recorded heart rate variability (HRV) and whether they felt a particular sensation (details omitted). Whether they reported...
  15. A

    Incorporating correlation between parameters using variation-covariance matrix

    Hi all, My colleagues and I are working on a project (i.e., health economics model) where we have fitted parametric curves (using Weibull, Exponential, Gompertz, Log-logistic, Log-normal, and Gamma distributions) to Kaplan-Meier data. In the project, we have estimated various survival curves...
  16. C

    Correlation between nominal variables

    Hi all, I'm currently working on a dataset extracted from a questionnaire and entered and coded in SPSS. Im trying to show correlation/relationships between a range of demographic dependant variables and one outcome variable. The data is nominal and often on a scale (ie.how important would...
  17. 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...
  18. 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...
  19. 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...
  20. D

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

    Do you think there is any correlation between these two variables? scatterplot: http://www.directupload.net/file/d/3641/5g58d9hx_jpg.htm data with software R: variable sd.prices: