As early as 3500 years ago, shadows of sticks were used as a primitive instrument for indicating the passage of time through the day. The stick came to be called a "gnomon" or "one who knows." Early Babylonian obelisks were designed to determine noon. The development of trigonometry by Greek mathematicians meant that hour lines…

One of the main objectives in meta-analysis is to estimate the overall effect size by calculating a confidence interval (CI). The usual procedure consists of assuming a standard normal distribution and a sampling variance defined as the inverse of the sum of the estimated weights of the effect sizes. But this procedure does not take into account…

It has been widely reported that in computerized adaptive testing some examinees may get much lower scores than they would normally if an alternative paper-and-pencil version were given. The main purpose of this investigation is to quantitatively reveal the cause for the underestimation phenomenon. The logistic models, including the 1PL, 2PL, and…

The demands of basic math skills often limit the ability of students with autism spectrum disorders to master purchasing skills. This study examined the use of counting-on math skills in conjunction with the next-dollar strategy to enhance independent purchasing skills. Four students with autism and intellectual disabilities successfully acquired…

Recent drug studies have investigated the incidence of blood clots among patients using the Ortho Evra[R] birth control patch. In this article, the author describes an investigation of oestrogen levels in the body resulting from the application of the Ortho Evra[R] birth control patch versus daily use of Ortho-Cyclen[R] birth control pills.…

A method is derived for the numerical evaluation of the error term arising in some Gauss-type formulae modified so as to approximate Cauchy Principal Value integrals. The method uses Chebyshev polynomials of the first kind. (Contains 1 table.)

Perceptual grouping is a pre-attentive process which serves to group local elements into global wholes, based on shared properties. One effect of perceptual grouping is to distort the ability to estimate the distance between two elements. In this study, biases in distance estimates, caused by four types of perceptual grouping, were measured across…

We describe and analyze a situation involving symbolic representation and graphical visualization of the solution of a system of two linear differential equations, using a computer algebra system. Symbolic solution and graphical representation complement each other. Graphical representation helps to understand the behavior of the symbolic…

Chronometric studies of language and memory processing typically emphasize changes in mean response time (RT) performance across conditions. However, changes in mean performance (or the lack thereof) may reflect distinct patterns at the level of underlying RT distributions. In seven experiments, RT distributional analyses were used to better…

In this research, the author addresses whether the application of unidimensional item response models provides valid interpretation of test results when administering items sensitive to multiple latent dimensions. Overall, the present study found that unidimensional models are quite robust to the violation of the unidimensionality assumption due…

Duration judgment has not been comprehensively examined in autism spectrum disorders (ASD), despite reports of perceptual idiosyncrasies in these individuals. Time estimation, production, and reproduction were tested in 25 individuals with ASD and 25 controls matched group-wise on age and IQ. Individuals with ASD performed comparably to matched…

We analysed the heating curve of water which is described in textbooks. An experiment combined with some simple heat transfer calculations is discussed. The theoretical behaviour can be altered by changing the conditions under which the experiment is modelled. By identifying and controlling the different parameters involved during the heating…

The Commonwealth of Pennsylvania plans to develop a new statewide evaluation system for teachers and principals in its public schools by school year 2013-2014. To inform the development of this evaluation system, the Team Pennsylvania Foundation (Team PA) undertook the first phase of the Pennsylvania Teacher and Principal Evaluation…

The Commonwealth of Pennsylvania plans to develop a new statewide evaluation system for teachers and principals in its public schools by school year 2013-2014. To inform the development of this evaluation system, the Team Pennsylvania Foundation (Team PA) undertook the first phase of the Pennsylvania Teacher and Principal Evaluation…

The purpose of this qualitative case study was to examine the modeling of technology by mathematics professors in two universities in teaching required courses for secondary level pre-service mathematics teachers. Six professors participated in this case study. Their responses were documented in pre- and post-interviews and data were gathered from…