Because of criticisms leveled at statistical hypothesis testing, some researchers have argued that measures of effect size should replace the significance-testing practice. We contend that although effect-size measures have logical appeal, they are also associated with a number of limitations that may result in problematic interpretations of them…

Providing a better education for visually-impaired learners is an objective pursued by many scientists and academics. Over the last few decades, in particular, the introduction of new technologies into education has created a number of innovative tools to assist in improving educational methods. One of the key areas where such innovations can be…

Multiple comparison procedures for controlling familywise Type I error and the false discovery rate are described and compared, including the traditional Bonferroni correction, a sequential (step-up) Bonferroni procedure (Hochberg, 1988), and a sequential false discovery rate procedure proposed by Benjamini and Hochberg (1995). Motivation for…

The National Board for Certified Counselors (NBCC) is the largest counselor certification agency in the U.S. and is widely recognized as a national credential based upon training, experience, and performance on a written examination. NBCC has developed two examinations: the National Counselor Examination (NCE) and the National Career Counselor…

The Z-variance and Box-Scheffe tests for homogeneity of variance are both relatively simple to perform and readily utilized in complex, multi-factor designs. The Z-variance test is not robust against non-normality; the Box-Scheffe test is robust against non-normality but is not nearly as powerful as the Z-variance test. (Author/BJG)

Evaluates these hypotheses: 1) psychological test indices of organic impairment are more frequent in Tourette patients than in a normal population, and 2) signs of organic impairment are more frequent in Tourette patients on psychiatric, neurological, and electroencephalographic examination than in the general population. (Author/RC)

The performance of 79 elementary school students referred for learning disability evaluation was compared on the Kaufman Assessment Battery for Children (K-ABC), the Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Woodcock-Johnson Psychoeducational Battery (WJPEB). Pearson product-moment correlations were performed on the global…

The treatment of covariance matrices given by McDonald (1974) can be readily modified to cover hypotheses prescribing zeros and equalities in the correlation matrix rather than the covariance matrix, still with the convenience of the closed-form Least Squares solution and the classical Newton method. (Author/RC)

Supported in part by a grant (M-628) from the United States Public Health Service, National Institutes of Health.