Assessing standardized contrast effects in ANCOVA: Confidence intervals, precision evaluations, and sample size requirements.

ABSTRACT: Standardized effect sizes and confidence intervals are useful statistical assessments for comparing results across different studies when measurement units are not directly comparable. This paper aims to describe and compare confidence interval estimation methods for the standardized contrasts of treatment effects in ANCOVA designs. Sample size procedures are also presented to assure that the resulting confidence intervals yield informative estimation with adequate precision. Exact interval estimation approach has theoretical and empirical advantages in coverage probability and interval width over the approximate interval procedures. Numerical investigations of the existing method reveal that the omission of covariate variables has a negative impact on sample size calculations for precise

SUBMITTER: Shieh G 

PROVIDER: S-EPMC9955653 | biostudies-literature | 2023

REPOSITORIES: biostudies-literature