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ERIC Number: EJ911226
Record Type: Journal
Publication Date: 2010-Dec
Pages: 12
Abstractor: As Provided
Reference Count: 9
ISBN: N/A
ISSN: ISSN-1076-9986
Confidence Intervals for True Scores Using the Skew-Normal Distribution
Garcia-Perez, Miguel A.
Journal of Educational and Behavioral Statistics, v35 n6 p762-773 Dec 2010
A recent comparative analysis of alternative interval estimation approaches and procedures has shown that confidence intervals (CIs) for true raw scores determined with the Score method--which uses the normal approximation to the binomial distribution--have actual coverage probabilities that are closest to their nominal level. It has also recently been shown that the skew-normal distribution yields a better approximation to the binomial distribution than the normal distribution. This article thus evaluates the benefits of using the skew-normal approximation for interval estimation of true scores. Three different CIs for true scores based on the skew-normal approximation are considered, and a simulation study is conducted whose results reveal that none of these skew-normal CIs is more accurate than the conventional Score CI in terms of probability coverage. Thus, skew-normal CIs, which incur a substantial computational cost, do not seem to be an advisable alternative for interval estimation of true scores. (Contains 4 figures.)
SAGE Publications. 2455 Teller Road, Thousand Oaks, CA 91320. Tel: 800-818-7243; Tel: 805-499-9774; Fax: 800-583-2665; e-mail: journals@sagepub.com; Web site: http://sagepub.com
Publication Type: Journal Articles; Reports - Evaluative
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A