SAMPAL: A Program for Determining Sample Sizes for Testing and Estimating Coefficient Alpha and for Comparing Two Alpha Coefficients

摘要

Coefficient alpha is one of the most widely reported measures of internal consistency. Although there have been hypothesis tests developed for coefficient alpha (e.g., Feldt, Woodruff, & Salih, 1987), the researcher might first consider estimating sample size for determining statistical significance. Sample-size formulas for testing the hypothesis that the sample coefficient alpha differs from the theoretical coefficient alpha with a given power and for estimating coefficient alpha with a specified precision were developed by Bonett (2002). Furthermore, he also derived a sample-size formula for testing the difference between alpha coefficients for specific values of power (Bonett, 2003). Therefore, the purpose of the user-friendly, stand-alone program was to compute the estimated sample sizes for aiding researchers in planning their study.