The effects of nonnormal distributions on confidence intervals around the standardized mean difference: bootstrap and parametric confidence intervals.
The standardized group mean difference, Cohen's d, is among the most commonly used and intuitively appealing effect sizes for group comparisons. However, reporting this point estimate alone does not reflect the extent to which sampling error may have led to an obtained value. A confidence interval e...
| Publicado en: | Educational & Psychological Measurement Vol. 65; no. 1; pp. 51 - 70 |
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| Autor principal: | |
| Formato: | equations & formulas research tables/charts Journal Article |
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Sage Publications Inc.
Feb2005
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| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=106581995&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 106581995 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 00131644 EPM jtl: Educational & Psychological Measurement issn: 00131644 maglogo: Y pubinfo: dt: Feb2005 vid: 65 iid: 1 pid: 344 pub: Sage Publications Inc. place: Thousand Oaks, California artinfo: ui: 106581995 15904757 2005037712 10.1177/0013164404264850 106581995 ppf: 51 ppct: 19 formats: tig: atl: The effects of nonnormal distributions on confidence intervals around the standardized mean difference: bootstrap and parametric confidence intervals. aug: au: Kelley K affil: 118 Haggar Hall, Dept of Psychology, University of Notre Dame, Notre Dame, IN 46556; kkelley@nd.edu sug: subj: Confidence Intervals Evaluation Effect Size Simulations Human ab: The standardized group mean difference, Cohen's d, is among the most commonly used and intuitively appealing effect sizes for group comparisons. However, reporting this point estimate alone does not reflect the extent to which sampling error may have led to an obtained value. A confidence interval expresses the uncertainty that exists between d and the population value, delta, it represents. A set of Monte Carlo simulations was conducted to examine the integrity of a noncentral approach analogous to that given by Steiger and Fouladi, as well as two bootstrap approaches in situations in which the normality assumption is violated. Because d is positively biased, a procedure given by Hedges and Olkin is outlined, such that an unbiased estimate of delta can be obtained. The bias-corrected and accelerated bootstrap confidence interval using the unbiased estimate of delta is proposed and recommended for general use, especially in cases in which the assumption of normality may be violated. pubtype: Academic Journal doctype: equations & formulas research tables/charts Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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