# test if two correlations are statistically different

I want to test wheather two correlations (1.correlation between snow depth and winter temperature, 1.correlation between snow depth and winter precipitation) are statistically different. I think I should use the z-test, but not sure how. Can anyone help? Thanks!

### Comments for test if two correlations are statistically different

 Feb 11, 2011 Compare Statistical Correlations by: Staff The question: I want to test whether two correlations are statistically different.I think I should use the z-test, but not sure how.1. correlation between snow depth and winter temperature, 2. correlation between snow depth and winter precipitation Can anyone help? Thanks!The answer:You didn’t say, but I assume the following:1.you have developed a (proportional) linear relationship for the form y = mx + b between the independent and dependent variables for both datasets (temperature & snow depth; and winter precipitation & snow depth)2.you have computed a Pearson r (linear) correlation for each of the two datasets (temperature & snow depth; and, winter precipitation & snow depth).I believe your question is: How do you test the significance of the Pearson r value at a given confidence level? Here are five, free on-line calculators which you may find helpful:http://www.wessa.net/corr.wasphttp://web.mst.edu/~psyworld/rcalculator.htmhttp://faculty.vassar.edu/lowry/tabs.htmlhttp://www.quantitativeskills.com/sisa/statistics/correl.htmhttp://www.fon.hum.uva.nl/Service/Statistics/Two_Correlations.htmlI’m also going to refer you to an example of how to use the z-value and standard deviation to compute the margin of error:http://www.solving-math-problems.com/question-on-averages-margin-of-error.htmlThanks for writing.Staff www.solving-math-problems.com

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