The Beginning of Statistical Inference: Comparing two Data Sets

The development of school students' understanding of comparing two data sets is explored through responses of students in individual interview settings. Eighty-eight students in grades 3 to 9 were presented with data sets in graphical form for comparison. Student responses were analysed according to a developmental cycle which was repeated in two contexts: one where the numbers of values in the data sets were the same and the other where they were different. Strategies observed within the developmental cycles were visual, numerical, or a combination of the two. The correctness of outcomes associated with using and combining these strategies varied depending upon the task and the developmental level of the response. Implications for teachers, educational planners and researchers are discussed in relation to the beginning of statistical inference during the school years. This revised version was published online in July 2006 with corrections to the Cover Date.     

Force– and power–time curve comparison during jumping between strength-matched male and female basketball players

The purpose of this study was to compare force– and power–time curve variables during jumping between Division I strength-matched male and female basketball athletes. Males (n?=?8) and females (n?=?8) were strength matched by testing a one-repetition maximum (1RM) back squat. 1RM back squat values were normalised to body mass in order to demonstrate that strength differences were a function of body mass alone. Subjects performed three countermovement jumps (CMJ) at maximal effort. Absolute and relative force– and power–time curve variables from the CMJs were analysed between males and females. Average force– and power–time curves were generated for all subjects. Jump height was significantly greater (p?≤?.05) in males than females. Absolute force was higher in males during the concentric phase, but not significantly different (p?≥?.05) when normalised to body mass. Significance was found in absolute concentric impulse between sexes, but not when analysed relative to body mass. Rate of force development, rate of power development, relative peak force, and work were not significantly different between sexes. Males had significantly greater impulse during the eccentric phase as well as peak power (PP) during the concentric phase of the CMJ than did females in both absolute and relative terms. It is concluded that sex differences are not a determining factor in measured force during a CMJ when normalised to body mass between strength-matched subjects. However, eccentric phase impulse and concentric phase PP appear to be influenced by sex differences independent of matching strength levels.     

Needs Assessment Across Disciplines

The needs assessment process, as a tool for decision making, continues to enjoy high visibility in the professional literature, especially in the area of training and human resource development. This literature review explores needs assessment in selected disciplines and provides generalizations about its application. Five needs assessment variables guided our survey of the purposes and methods of the needs assessments described in 106 articles in five general areas (applied sciences, education/technology, medicine/allied health, business/information sciences, and human/public services).     

A comparison of nonreferred,learning-disabled,and mildly mentally retarded students utilizing the social skills rating system

The assessment of social skills deficits has received wide support. Recently, the Social Skills Rating System (SSRS) has been developed to assist professionals in assessing social skills. In this study, the Social Skills Rating System was used to compare students who had already been classified as learning disabled (n = 20) and mildly mentally retarded (n = 20) with a group of nonreferred students (n = 20). The results showed that as a group students with disabilities scored significantly lower than the nonreferred group on social skills and significantly higher in problem behaviors. A discriminant analysis revealed that the SSRS was able to predict group membership broadly (e.g., handicapped versus nonhandicapped) but not specifically (e.g., learning disabled, mentally retarded). Moderate Pearson correlations between parents and teacher ratings indicated some consistencies between raters. However, low kappa coefficients showed that parents and teachers are likely to identify different students as having social skills deficits and problem behaviors. Suggestions are given for utilizing the SSRS with other techniques such as interviews and observations in the assessment and remediation of social skills problems.