Wow, ViAnn Beadle, you are my hero!!!:))) Now I can uninstall the v.17:))
Really, some things are not written anywhere, and they are so hard to find!
I thank you all for your help, it means so much to me!
Ok, I will write this down in detail. I have a sample of 556 patients with
prostate cancer. Biopsies were taken before the surgical intervention. I
grouped the positive no. of biopsies in 3 groups (Group 1 - 1-2 positive
biopsies, Group 2 - 3-4 positive biopsies, Group 3 - 5-10 positive
biopsies), so this would be the ordinal, independent variable. Biochemical
relapse after intervention, a nominal, dichotomous variable, yes or no
(involves a 3 year period).
Task: correlation and get info on how I could predict the relapse chances
based on positive fragments group.
Problem: Choosing the appropriate tests. I have read a lot in the past week,
but it seems there is a problem with correlation between ordinal and
nominal, no manual likes to talk about it, especially if the outcome
variable is the nominal.
After a looooong studying period I have chosen Cramer's v and lambda,
because books say that: Kendall-tau can be used only with 2 ordinals, tau-b
if (no. columns=no. rows), tau-c if (no. columns<>no. rows), Pearson r only
for scale and normally distributed, Spearman only with 2 ordinals, Gamma and
Sommer's d only with 2 ordinals; and I quoted above from a book regarding
the ordinal+nominal test that says Cramer's V is appropriate.
As I understand, nominal tests can be used for ordinals, some non-parametric
for parametric, only you loose some power of the test (e.g. Wilcoxon for a
normally distributed scale). But Cramer's and lambda gave me even this way
positive, statistically significant results.:))
Now, I want to do a binomial logistic regression test, but first I have to
learn about it more, and how to interpret it.
So Sommers'd for Kendall is like lambda for Cramer's???
It would be awesome to have a list which shows the tests paired in 3 , like:
(test which shows existence of correlation )-(test for measure the power of
the correlation) - (test for predicting the chances or calculating the
outcome variable based on independent)
View this message in context: http://spssx-discussion.1045642.n5.nabble.com/correlation-and-regression-for-ordinal-and-nominal-dependent-tp5471812p5476605.html
Sent from the SPSSX Discussion mailing list archive at Nabble.com.
To manage your subscription to SPSSX-L, send a message to
LISTSERV@LISTSERV.UGA.EDU (not to SPSSX-L), with no body text except the
command. To leave the list, send the command
For a list of commands to manage subscriptions, send the command