Phi

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__**Phi (Ø)** __ - is a chi square-based measure of association. Appropriate for nominally measured variables that have been organized into a 2 x 2 bivariate table. =====

- **One of the attractions of Phi is that it is easy to calculate:** Step 1: Simply divide the value of the obtained chi square by N Step 2: Find the square root of the quantity you found in step 1. The resulting value is phi.


 * EXAMPLE: Table 13.1 (Healey)**

__Accreditation Status__ Chi square (obtained) =10.78 N = 100 So; 10.78/100, and get the square root of the quantity you found... Ø = 0.33
 * Employment Status || Accredited || Not Accredited || Totals ||
 * Working as a social worker || 30 || 10 || 40 ||
 * Not working as a social worker || 25 || 35 || 60 ||
 * Totals || 55 || 45 || 100 ||

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- For a 2 x 2 table, phi ranges in value from 0 (no association) to 1.00 ( perfect association). The closer to 1.00, the stronger the relationship; the closer to 0.00, the weaker the relationship. ===== -For tables larger than 2 x 2 ( specially, for tables with more than two columns and more than two rows), the upper limit of Phi can exceed 1.00. This makes Phi difficult to interpret, and more general form of the statistics called Cramer's V.