Three procedures used to control Type I error rate in stepwise regression analysis are forward selection, backward elimination, and true stepwise. In the forward selection method, a model of the dependent variable is formed by choosing the single best predictor; then the second predictor which makes the strongest contribution to the prediction of…

Arguments have recently been put forth that standard textbook procedures for determining the sample size necessary to achieve a certain level of power in a completely randomized design are incorrect when the dependent variable is fallible because they ignore measurement error. In fact, however, there are several correct procedures, one of which is…

Ridge regression is presented as an analytic technique to be used when predictor variables in a multiple linear regression situation are highly correlated, a situation which may result in unstable regression coefficients and difficulties in interpretation. Ridge regression avoids the problem of selection of variables that may occur in stepwise…

The normal course of family adaptation to pregnancy, birth, and early parenting is examined in this study, and variables predictive of difficulties in family adjustment during this period are investigated. Subjects were 89 married couples and 9 women whose husbands did not participate. The women had a mean age of 28 years; 46 were pregnant for the…

The predictive value of the high-school-level battery of the tests of General Educational Development (GED) for two-year college academic performance was investigated. GED tests scores were examined to determine if they could substitute for a complete high school record as a source of predictor data. Student record data from a registrar's office…

The predictive validity of the new Medical College Admission Test (MCAT) was examined; the validity coefficients were compared to those obtained from previous versions of the MCAT and from performance data gathered early in a first-year basic science program. Data were collected from about 400 medical students, including: (1) MCAT…

When the school or district is the unit of analysis in school effects research, the outcome of interest is mean achievement, and the variance explained by school or district level predictors is between schools or between districts. When the individual is the unit of analysis, the outcome of interest is individual achievement and the variance…

A study compared elementary school students' classroom reading achievement levels to their chronological ages, sex, race, and parents' educational levels. Subjects were 168 children in grades one through four. The results indicated that reading levels did covary with parent education levels, with an additional effect of race indicated. No main or…

The purposes of this paper are to provide an explanation of the way in which suppressor variables operate in multiple regression, and to provide illustrations of their effects with actual social science data. Examples are reviewed in which one predictor accounts for more of the variance in the dependent variable when another predictor is included,…

This paper reviews ten studies on the effects of television cartoon violence on aggressive behavior in children and discusses possible reasons for the inconsistent results. Methodology and results of field and laboratory studies are compared, and study limitations are noted. The impact of cartoons is discussed in terms of human vs. animal…

Since migration is strongly influenced by economic variables, an economic model was developed to identify, locate, and track migrant and seasonal farmworkers as they move throughout the United States. Focusing on the Florida-based migrant agricultural workers who migrated at least once during the past five years, the model included the following…

Pre-selection criteria were developed to obtain a profile of student nurses who would compute a community college nursing program, and student nurses who would leave the program prior to completion. The battery consisted of tests and questionnaires based upon cognitive, personality/attitude, vocational preference, and socioeconomic status domains.…

A review of current procedures for selecting students for graduate programs in psychology reveals a number of problems due to predictor, criterion, and methodological variables. The idea is advanced that with the multiplicity of procedures used, plus the number of students applying to graduate programs in psychology, the effort on the part of…

Previous research on communication apprehension has revealed a reduction in student apprehension over a semester-length course in speech communication. Further research indicates, however, that, while most students do experience a reduction, a sizable percentage actually report an increase. This study sought to determine the difference between…

A linear classification rule (used with equal covariance matrices) was contrasted with a quadratic rule (used with unequal covariance matrices) for accuracy of internal and external classification. The comparisons were made for seven situations which resulted from combining three data conditions (equal and unequal covariance matrices, minimal and…