contingency table

  1. A

    How to check for multicolinearity between two categorical variables when their contingency table contains many zero entries?

    Problem: I have to build a multiple regression model where most of my predictor (independent) variables are categorical (nominal) but I'm running into a few problems due to some of the predictors being (perfectly) colinear. So I need to check for multicolinearity and remove redundant predictors...
  2. J

    Contingency Table Analysis by chi square problem

    I am trying to figure out a chi square problem, and I keep getting stuck. The problem reads: A researcher tested single mosquitoes from five different locations for the presence of a particular virus and obtained the following data: Location A B C D E w/ virus 3 7...
  3. J

    analysis for sparse contingency table

    I am analyzing a 2x2x3x2 contingency table. The covariates are treatment (2 different kinds, TR1 and TR2, both binary), location of treatment (3 levels A, B, C), and the outcome is an event that either occurred or did not occur. The table is large compared to the sample size, and observing the...
  4. S

    validity of data arrangement in a 2x2 table for fishers exact test.

    Hi, I have two conditions (A and B) to which the subjects has been exposed to. There are two responses to those conditions yes or no. I can arrange the data in a 2x2 table in two different ways: The P value for fishers exact test is 0.0028. This table for fishers exact test...
  5. F

    Question how to build the contingency table

    Hi all, I have two lists of genes as follows: DEList has 282 gene names AllList has 32805 gene names DEList is a subset of AllList. In both lists I've looked for genes which have a specific parameter (e.g. binding site for pol3 and binding site for pol2). The results of this...
  6. J

    What statistical calculation to use and which R function?

    Here's the data I have... I have a "national" sample (the control) showing the actual number and percentage of people in the sample that have a specific characteristic. Let's say there's data on 10,000 people that are all classified as either loving cats or hating cats (Yes or No). I then...
  7. J

    Influence of frequency on contigency table

    If there are binomial observations, and binomial conditions, what is the influence of frequency and how to determine the "correct" frequency. For example, say there is a engine light that is either on or off. And the cars either had the oil changed or they didn't by a mechanic who could tell...
  8. G

    Chi-Square: Is effect A larger than effect B?

    Dear All, I would like to test hypotheses like the following example: Effect A is weaker than effect B. For Effects A and B, I have a 2 (error: present vs. absent) x 2 (group: control vs. experimental) contingency table, thus getting chi and e.g. a phi-coefficient. My question is: How...
  9. Austringer

    Cramer's V in XLSTAT

    Hi all, I performed contingency table tests and I want to know how to interpret Cramer's V test stat. I am using Cramer's V as my tables violate basic Chi-square assumptions of theoretical frequencies >5, i.e. my freqs. <5 in tables such as below. Which p-value can I use to interpret the...
  10. S

    ANOVA/Regression

    Hi all, First timer here. I am hoping this is the right forum and that someone could point me in the right direction. I am analyzing a dataset which contains over 4500 points. Almost all the independent variables are indicator variables. It so happens that at some levels of the variables...
  11. S

    Sparsity in an m*n contingency table

    I am attempting to find a citation for or document the use of a correction factor for an m \times n contingency table with sparse data (for most of the tables, 20% to 80% of the cells have a value of 0). I have been working with a statistician who insists that adding 0.5 to each value is an...
  12. S

    permutation test on 2-factor contingency table

    Anyone has an idea on how to perform a permutation test on a 2-factor contingency table? In R? thanks!! :)
  13. T

    Pearson's chi-test for more than 2x2

    So, I have one stat book (Discovering Statistics by Andy Field; great book) that discusses Pearson's chi-test and how it's only applicable to a 2x2 contingency table with categorical data. The solution is to use the loglinear analysis for larger tables according to Andy. Another book I have...
  14. P

    deriving chi-square stat for contingency table

    Howdy! I'm attempting to derive the chi-square stat for a 2x2 contingency table, like: a | b ------ c | d The chi-square formula given is : (a+b+c+d)(ad- bc)^2 / ( (a+b)(a+c)(b+d)(c+d) ) I can derive all but the (ad-bc)^2 part of the formula. Any links or tips about how this formula...
  15. R

    contingency table: categories are not mutually exclusive, and data is not all paired

    Hi, I'm confused about what test I should be using and hope someone can help. Data: I have data from microbiological samples where the bacteria's sensitivity to various antibiotics was tested. A sample might have been tested for sensitivity to loads of different antibiotics (say up to...