The effects of age and body weight on anthropometric estimations of minimal wrestling weight in high school wrestlers

The purpose of this study was to determine the effects of age and body weight on anthropometric estimations of minimal wrestling weight (MWW) in high school wrestlers. Five hundred and twenty-two high school wrestlers (M age +/- SD = 16.45 +/- 1.03 years) volunteered as subjects for this study. The total sample (N = 522) was dichotomized by age (less than 16 years, n = 171; greater than or equal to 16 years, n = 351) and body weight (less than or equal to 62.60 kg, n = 252; greater than 62.60 kg, n = 270). Cross-validation analyses included examination of the constant error (CE), standard error of estimate (SEE), r, and total error (TE). The results indicated that the quadratic skinfold equation of Lohman (EQ1; Table 2) most accurately estimated MWW in each group. Furthermore, it was recommended that MWW be calculated from EQ1 using the conversion constants of Lohman ([(5.03/BD)-4.59] x 100) to estimate relative fat from body density.     

Effect of Unequal Variances in Proficiency Distributions on Type-I Error of the Mantel-Haenszel Chi-square Test for Differential Item Functioning

Empirical studies demonstrated Type-I error (TIE) inflation (especially for highly discriminating easy items) of the Mantel-Haenszel chi-square test for differential item functioning (DIF), when data conformed to item response theory (IRT) models more complex than Rasch, and when IRT proficiency distributions differed only in means. However, no published study manipulated proficiency variance ratio (VR). Data were generated with the three-parameter logistic (3PL) IRT model. Proficiency VRs were 1, 2, 3, and 4. The present study suggests inflation may be greater, and may affect all highly discriminating items (low, moderate, and high difficulty), when IRT proficiency distributions of reference and focal groups differ also in variances. Inflation was greatest on the 21-item test (vs. 41) and 2,000 total sample size (vs. 1,000). Previous studies had not systematically examined sample size ratio. Sample size ratio of 1:1 produced greater TIE inflation than 3:1, but primarily for total sample size of 2,000.     

Enhancing Memory Access for Less Skilled Readers

Less skilled readers’ comprehension often suffers because they have an impoverished representation of text in long-term memory; this, in turn, increases the difficulty of gaining access to backgrounded information necessary for maintaining coherence. The results of four experiments demonstrated that providing less skilled readers with additional explicit interconnections enhanced their text representations in memory and increased their ability to maintain coherence. Experiments 1a and 1b confirmed the finding that less skilled readers were not disrupted by global inconsistencies. Experiments 2a and 2b showed that text manipulations designed to enhance the accessibility of global information led to less skilled readers being disrupted by global inconsistencies.     

Exploiting Distance Technology to Foster Experimental Design as a Neglected Learning Objective in Labwork in Chemistry

This paper deals with the design process of a remote laboratory for labwork in chemistry. In particular, it focuses on the mutual dependency of theoretical conjectures about learning in the experimental sciences and technological opportunities in creating learning environments. The design process involves a detailed analysis of the expert task and knowledge, e.g., spectrophotometry as a method for the determination of the concentration of a compound in a solution. In so doing, modifications in transposing tasks and knowledge to the learning situation can be monitored. The remote laboratory is described, as well as the specific features that alter the degree of fidelity of the learning situation in comparison with the expert one. It is conjectured that these alterations might represent actual benefits for learning.     

Contents of Volume 49

Volume Contents

Contents of Volume 49     

Solitary and Collaborative Pretense Play in Early Childhood: Sources of Individual Variation in the Development of Representational Competence

This study evaluates sources of individual variation in child pretense play as an expression of emerging mental representation. Family sociodemographic characteristics, maternal personological characteristics, and maternal affective and cognitive play behaviors, as well as children's gender, language competence, and play, were examined simultaneously. Naturalistic child solitary play and child collaborative play with mother were videorecorded in 141 20–month-olds. Child solitary play, child-initiated and mother-initiated collaborative play with mother, and maternal demonstrations and solicitations of play were then coded into nonsymbolic and symbolic acts. Zero-order relations obtained between child play and, respectively, child gender and language, family SES, and maternal verbal intelligence, personality, physical affection, and play demonstrations and solicitations. Structural equation modeling supported the following unique predictive relations: Child language and mothers' symbolic play positively influenced child collaborative play, and child gender and mothers' verbal intelligence predicted child solitary play. Child gender and mothers' verbal intelligence and physical affection influenced mothers' play and so influenced child collaborative play indirectly. The cognitive advantages of child play and maternal influences on child play are placed in an adaptive parenting framework.