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Power and sample size calculations for comparison of two regression lines with heterogeneous variances

Conceptualization: Gwowen Shieh. Data curation: Gwowen Shieh. Formal analysis: Gwowen Shieh. Funding acquisition: Gwowen Shieh. Investigation: Gwowen Shieh. Methodology: Gwowen Shieh. Project administration ... : Gwowen Shieh. Resources: Gwowen Shieh. Software: Gwowen Shieh. Supervision: Gwowen Shieh. Validation: Gwowen Shieh. Visualization: Gwowen Shieh. Writing – original draft: Gwowen Shieh. Writing

On tests of treatment-covariate interactions: An illustration of appropriate power and sample size calculations

The appraisals of treatment-covariate interaction have theoretical and substantial implications in all scientific fields. Methodologically, the detection of interaction between categorical treatment levels and continuous covariate variables is analogous to the homogeneity of regression slopes test in the context of ANCOVA. A fundamental assumption of ANCOVA is that the regression...

Exact Power and Sample Size Calculations for the Two One-Sided Tests of Equivalence

Equivalent testing has been strongly recommended for demonstrating the comparability of treatment effects in a wide variety of research fields including medical studies. Although the essential properties of the favorable two one-sided tests of equivalence have been addressed in the literature, the associated power and sample size calculations were illustrated mainly for selecting...

A systematic approach to designing statistically powerful heteroscedastic 2 × 2 factorial studies while minimizing financial costs

Background The 2 × 2 factorial design is widely used for assessing the existence of interaction and the extent of generalizability of two factors where each factor had only two levels. Accordingly, research problems associated with the main effects and interaction effects can be analyzed with the selected linear contrasts. Methods To correct for the potential heterogeneity of...

Choosing the best index for the average score intraclass correlation coefficient

The intraclass correlation coefficient (ICC)(2) index from a one-way random effects model is widely used to describe the reliability of mean ratings in behavioral, educational, and psychological research. Despite its apparent utility, the essential property of ICC(2) as a point estimator of the average score intraclass correlation coefficient is seldom mentioned. This article...

Confidence intervals and sample size calculations for the weighted eta-squared effect sizes in one-way heteroscedastic ANOVA

Effect size reporting and interpreting practices have been extensively recommended in academic journals when primary outcomes of all empirical studies have been analyzed. This article presents an alternative approach to constructing confidence intervals of the weighted eta-squared effect size within the context of one-way heteroscedastic ANOVA models. It is shown that the...

A comparison of two indices for the intraclass correlation coefficient

In the present study, we examined the behavior of two indices for measuring the intraclass correlation in the one-way random effects model: the prevailing ICC(1) (Fisher, 1938) and the corrected eta-squared (Bliese & Halverson, 1998). These two procedures differ both in their methods of estimating the variance components that define the intraclass correlation coefficient and in...

The impact of ignoring random features of predictor and moderator variables on sample size for precise interval estimation of interaction effects

Gwowen Shieh 0 ) Department of Management Science, National Chiao Tung University , 1001 Ta Hsueh Road, Hsinchu, Taiwan 30050 , Republic of China The influence of the joint distribution of

Estimation of the simple correlation coefficient

GWOWEN SHIEH 0 0 National Chiao Tung University , Hsinchu, Taiwan This article investigates some unfamiliar properties of the Pearson product-moment correlation coefficient for the estimation of

Optimal sample sizes for precise interval estimation of Welch’s procedure under various allocation and cost considerations

Gwowen Shieh 0 Show-Li Jan 0 0 S.-L. Jan Department of Applied Mathematics, Chung Yuan Christian University , Chungli, Taiwan 32023 , Republic of China 1 ) Department of Management Science

Sample size determination for confidence intervals of interaction effects in moderated multiple regression with continuous predictor and moderator variables

GWOWEN SHIEH 0 0 National Chiao Tung University , Hsinchu, Taiwan Moderated multiple regression (MMR) has been widely employed to analyze the interaction or moderating effects in behavior and

Optimal sample sizes for Welch’s test under various allocation and cost considerations

Show-Li Jan 0 Gwowen Shieh 0 0 S.-L. Jan Department of Applied Mathematics, Chung Yuan Christian University , Chungli, Taiwan 32023 , Republic of China 1 ) Department of Management Science

Detection of interactions between a dichotomous moderator and a continuous predictor in moderated multiple regression with heterogeneous error variance

GWOWEN SHIEH 0 0 National Chiao Tung University , Hsinchu, Taiwan Moderated multiple regression (MMR) has been widely used to investigate the interaction or moderating effects of a categorical

Methodological and computational considerations for multiple correlation analysis

GWOWEN SHIEH 0 CHIEN-FENG KUNG 0 0 National Chiao Tung University , Hsinchu, Taiwan The squared multiple correlation coefficient has been widely employed to assess the goodness-of-fit of linear