Can You Calculate a P-Value for Correlation Between Non-Parametric Data?

  • Thread starter Thread starter sobored
  • Start date Start date
  • Tags Tags
    Statistic
Click For Summary

Homework Help Overview

The discussion revolves around calculating a p-value for the correlation between two non-parametric data groups, specifically focusing on the use of Pearson's correlation coefficient and its appropriateness given the nature of the data.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to calculate a p-value for the correlation between two groups using Pearson's coefficient, despite noting that the data is non-parametric. Some participants question the appropriateness of using Pearson's correlation and suggest considering Spearman's correlation instead. There are inquiries about the sample size and the type of data involved, as well as discussions about the possibility of using a Student's T-test for p-value prediction.

Discussion Status

Participants are exploring the implications of using parametric versus non-parametric methods for correlation analysis. There is a recognition that more information about the data set is necessary to recommend an appropriate statistical test. Some guidance has been offered regarding the use of Spearman's correlation and the need for clarity on the experimental design.

Contextual Notes

The original poster has indicated that both groups consist of 35 continuous samples, which raises questions about the validity of using parametric tests in this context. The discussion also touches on the original poster's familiarity with calculating p-values for differences between groups, contrasting with their uncertainty regarding correlation.

sobored
Messages
52
Reaction score
0
I have made a correlation between group A and B and the pearsson coefficient constant, r, is at 0.97. The values are expression levels and hence they are non-parametric. I wonder how can i calculate the p-value of this correlation between group A and B? I know how to calculate the p-value for the difference between group A and B, but not for the correlation between group A and B.


Thanks for any inputs!
 
Physics news on Phys.org
Pearson's correlation coefficient is a parametric statistic. If your data require a non-parametric test (how did you determine this?), then you can't use Pearson's correlations, but should instead be using Spearman's correlation coefficient, which is the non-parametric counterpart to Pearson's. But, nobody will be able to help you beyond that without more information about the data set you're working with. What's your sample size? Do you have continuous or integer data, random or fixed variables, etc? Basically, without knowing your experimental design, nobody can recommend an appropriate statistical test.
 
Moonbear said:
Pearson's correlation coefficient is a parametric statistic. If your data require a non-parametric test (how did you determine this?), then you can't use Pearson's correlations, but should instead be using Spearman's correlation coefficient, which is the non-parametric counterpart to Pearson's. But, nobody will be able to help you beyond that without more information about the data set you're working with. What's your sample size? Do you have continuous or integer data, random or fixed variables, etc? Basically, without knowing your experimental design, nobody can recommend an appropriate statistical test.


Thanks for helping me out.

Both groups have 35 samples and the values are continues. Can i use student T test to predict this p-value, assumming that i use the parametric way?
 
sobored said:
Thanks for helping me out.
Both groups have 35 samples and the values are continues. Can i use student T test to predict this p-value, assumming that i use the parametric way?
I believe you can; as explained in this link or http://faculty.vassar.edu/lowry/rsig.html. (Both from a Yahoo! search on significance test for correlation coefficient.)
 
Last edited:

Similar threads

Replies
4
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 9 ·
Replies
9
Views
3K
Replies
20
Views
4K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 24 ·
Replies
24
Views
3K
Replies
1
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 13 ·
Replies
13
Views
2K