Interval for the Correlation Coefficient

A 1 - a Cl on r can be derived using a modification of Fisher s Z transformation. The transformation has the form 

The researcher also uses the normal Z table (Table A) instead of Student s t table. The test is reasonably powerful, so long as 20. 

The lower limit value is then fotmd in Table O (Fisher s Z Transformation Table) for the corresponding r value. 

The upper limit is also found in Table O for the corresponding r value. The (1—a) 100% Cl is of the form R U. Let us use Example 2.1. Four steps are required for the calculator  

Step 1 Compute the basic interval, letting a = 0.05 and Zo5/2 = L96 (from Table A). 

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