Analysis of Covariance and Randomized Block Design with Heterogeneous Slopes

The authors compared the Type I error rate and the power to detect differences in slopes and additive treatment effects of analysis of covariance (ANCOVA) and randomized block (RB) designs with a Monte Carlo simulation. For testing differences in slopes, 3 methods were compared: the test of slopes from ANCOVA, the omnibus Block × Treatment interaction, and the linear component of the Block × Treatment interaction of RB. In the test for adjusted means, 2 variations of both ANCOVA and RB were used. The power of the omnibus test of the interaction decreased dramatically as the number of blocks used increased and was always considerably smaller than the specific test of differences in slopes found in ANCOVA. Tests for means when there were concomitant differences in slopes showed that only ANCOVA uniformly controlled Type I error under all configurations of design variables. The most powerful option in almost all simulations for tests of both slopes and means was ANCOVA.     

Is three-dimensional anthropometric analysis as good as traditional anthropometric analysis in predicting junior rowing performance?

Abstract With the use of three-dimensional whole body scanning technology, this study compared the 'traditional' anthropometric model [one-dimensional (1D) measurements] to a 'new' model [1D, two-dimensional (2D), and three-dimensional (3D) measurements] to determine: (1) which model predicted more of the variance in self-reported best 2000-m ergometry rowing performance; and (2) what were the best anthropometric predictors of ergometry performance, for junior rowers competing at the 2007 and 2008 Australian Rowing Championships. Each rower (257 females, 16.3?±?1.4 years and 243 males, 16.6?±?1.5 years) completed a performance and demographic questionnaire, had their mass, standing and sitting height physically measured and were landmarked and scanned using the Vitus Smart? 3D whole body scanner. Absolute and proportional anthropometric measurements were extracted from the scan files. Partial least squares regression analysis, with anthropometric measurements and age as predictor variables and self-reported best 2000-m ergometer time as the response variable, was used to first compare the two models and then to determine the best performance predictors. The variance explained by each model was similar for both male [76.1% (new) vs. 73.5% (traditional)] and female [72.3% (new) vs. 68.6% (traditional)] rowers. Overall, absolute rather than proportional measurements, and 2D and 3D rather than 1D measurements, were the best predictors of rowing ergometry performance, with whole body volume and surface area, standing height, mass and leg length the strongest individual predictors.     

Learning science by doing science: an authentic science process-learning model in postsecondary education

Research on understanding the full extent that an authentic science research experience engages students in how scientists think and act is sparse. ‘Learning-science-by-doing-science’ (LSDS) is an emerging self-guided process-learning model in postsecondary science education. It offers authentic science research opportunities that drive students to think and act like scientists. This study investigates the LSDS approach as a potential model for science learning at postsecondary level and aims to answer a main research inquiry – what are the students’ and teaching staff’s perceptions of students’ learning gains and the quality of their learning experiences in an authentic research environment within the LSDS model? To answer this question, data were collected from the students, alumni, instructors, teaching assistants and the program director via questionnaires, focus groups and interviews. Students’ and staff’s lived experiences and their perceptions on their authentic research experiences within the LSDS model were used to articulate the key attributes and stages of the LSDS model. The outcomes of this study can be used to help other science programs implement similar authentic research process learning approaches in their own contexts.     

Evaluation of an Innovative Interest-Based Post-School Transition Programme for Young People with Autism Spectrum Disorder

After leaving school, young people with autism spectrum disorder often struggle with social, educational and employment participation. A post-school transition programme underpinned by individualised case management, where mentees are guided to complete self-selected projects by mentors with multimedia skills, was evaluated using a qualitative approach. The programme’s impact on mentees’ social participation, emotional well-being, project skills and awareness of and transition to post-school options was examined. Eleven mentees (17–21 years), 12 family members and 7 mentors participated in semi-structured interviews. Mentors completed fortnightly records. Findings included positive impacts on mentees’ motivation and enjoyment, social participation, emotional well-being and skill development; and an appreciation of the programme flexibility and the high-quality mentor–mentee relationships. Some mentees developed their awareness of future options, while others struggled to articulate their goals. Two of 11 mentees transitioned to further education. Overall, the programme appeared to fulfil a critical need for nurturing, post-school transition programmes.     

Comparing Multidimensional and Unidimensional Proficiency Classifications: Multidimensional IRT as a Diagnostic Aid

This research examined the effect of scoring items thought to be multidimensional using a unidimensional model and demonstrated the use of multidimensional item response theory (MIRT) as a diagnostic tool. Using real data from a large-scale mathematics test, previously shown to function differentially in favor of proficient writers, the difference in proficiency classifications was explored when a two-versus one-dimensional confirmatory model was fit. The estimate of ability obtained when using the unidimensional model was considered to represent general mathematical ability. Under the two-dimensional model, one of the two dimensions was also considered to represent general mathematical ability. The second dimension was considered to represent the ability to communicate in mathematics. The resulting pattern of mismatched proficiency classifications suggested that examinees found to have less mathematics communication ability were more likely to be placed in a lower general mathematics proficiency classification under the unidimensional than multidimensional model. Results and implications are discussed.