339 children aged 6 and 7 at Oxford primary schools took part in a study of arithmetic. 204 of the children had been selected by their teachers as having mathematical difficulties and the other 135 children were unselected. They were assigned to an Addition Performance Level on the basis of a calculation pretest, and then given Dowker's (1998)…

This study evaluated the effects of color highlighting during a math computation task on performance accuracy and behavior of students with attention problems. Using a multiple baseline across participants design, three students solved math computation problems on worksheets with and without highlighting. Off-task behavior recorded from videotape…

It is unknown whether the Autism-spectrum quotient (AQ) can discriminate between Autism Spectrum Disorder (ASD) and Attention Deficit and Hyperactivity Disorder (ADHD) with or without comorbid Substance Use Disorder (SUD). ANOVA's were used to analyse the mean AQ (sub)scores of 129 adults with ASD or ADHD. We applied receiver operating…

Trigonometric parallax is a powerful method to work out the distance of celestial bodies, and it was used in the past to measure the distance of the Moon, Venus, Mars and nearby stars. We set up an observation campaign for high school and undergraduate students with the purpose to measure both the Moon's and Mars' parallax. To have a large enough…

Numerous studies have compared the Angoff standard-setting procedure to other standard-setting methods, but relatively few studies have evaluated the procedure based on internal criteria. This study uses a generalizability theory framework to evaluate the stability of the estimated cut score. To provide a measure of internal consistency, this…

The authors examined the robustness of multilevel linear growth curve modeling to misspecification of an autoregressive moving average process. As previous research has shown (J. Ferron, R. Dailey, & Q. Yi, 2002; O. Kwok, S. G. West, & S. B. Green, 2007; S. Sivo, X. Fan, & L. Witta, 2005), estimates of the fixed effects were unbiased, and Type I…

The subject of uncertainties (sometimes called errors) is traditionally taught (to first-year science undergraduates) towards the end of a course on statistics that defines probability as the limit of many trials, and discusses probability distribution functions and the Gaussian distribution. We show how to introduce students to the concepts of…

This paper develops an empirical occupational choice model that corrects for misclassification in occupational choices and measurement error in occupation-specific work experience. The model is used to estimate the extent of measurement error in occupation data and quantify the bias that results from ignoring measurement error in occupation codes…

This study investigated the possibility that apparent sex differences in IQ are at least partly created by the degree of sample restriction from the baseline population. We used a nationally representative sample, the 1970 British Cohort Study. Sample sizes varied from 6518 to 11,389 between data-collection sweeps. Principal components analysis of…

A simple, straightforward and efficient method is proposed for the calculation of the period of anharmonic oscillators as an energy series. The approach is based on perturbation theory and the method of Lindstedt-Poincare.

A simple algorithm for computing the partial fraction expansions of proper rational functions with multiple poles is presented. The main idea is to use the Heaviside's cover-up technique to determine the numerators of the partial fractions and polynomial divisions to reduce the multiplicities of the poles involved successively, without the use of…

This work presents an introductory development of fractional order derivatives and their computations. Historical development of fractional calculus is discussed. This paper presents how to obtain computational results of fractional order derivatives for some elementary functions. Computational results are illustrated in tabular and graphical…

A simple method based on the moment of forces and Archimedes' principle is described for finding density without measuring the mass and volume of an object. The method involves balancing two unknown objects of masses M[subscript 1] and M[subscript 2] on each side of a pivot on a metre rule and measuring their corresponding moment arms. The object…

In 3 experiments, the authors compared duration judgments of filled stimuli (tones) with unfilled ones (intervals defined by clicks or gaps in tones). Temporal generalization procedures (Experiment 1) and verbal estimation procedures (Experiments 2 and 3) all showed that subjective durations of the tones were considerably longer than those of…

Converting between degrees Celsius and degrees Fahrenheit isn't difficult. Remembering when to multiply by 5/9 or 9/5 and whether you have to add 32 or subtract 32 makes it fairly easy. Sometimes, though, fairly easy isn't easy enough. Students have trouble remembering the order of operations: "Do I add or subtract 32, and is that before or after…