A simplified mathematical model for the calculation of imprecision associated with the construction of a calibration line is presented. The model also aims at a discussion on variables that really affect it and to integrate the resulting imprecision with that caused by the other steps in the analytical method in order to calculate a real…

Counting can be done using a linear, exponential method or by using a technique incorporating a recursive process which gives a visual analysis of population data. Population estimates are based on assumptions about change brought about by immigration, emigration, deaths and births.

The greatest benefit of including leap year in the calculation is not to increase precision, but to show students that a problem can be solved without such presumption. A birthday problem is analyzed showing that calculating a leap-year birthday probability is not a frivolous computation.

None of the techniques -- sorting, scatter graphs, grouping, or calculating means -- that are highlighted in this work are particularly sophisticated, and yet their simplicity is often more than adequate for displaying the trends in data or for making comparisons in a convincing way. These are strategies that are easy to introduce to students and…

The aim of the study was to analyze the development of children's adaptive expertise in computing sums and differences up to 100. We defined the adaptive nature of children's strategy choices on the basis of problem (addition, subtraction), achievement, and strategy performance (accuracy, speed). Sixty-nine 2nd graders of high, above-average, or…

A two-year project was conducted, mainly with two goals, to make the students fluent in addition and subtraction and to have the students develop an understanding of computation that was strong enough to solve more than routine problems. The most common method for teaching children computation is teaching the standard procedures and then giving…

The calculations of uncertainties in the formula or molar masses of compounds are streamlined. Three rules of increasing complexity are proposed, which overestimate the uncertainty so there is little if any risk that the true values are missed.

In European countries, field studies investigate how citizens acquire knowledge of the new currency, the euro. In 3 laboratory experiments, the authors recruited 168 undergraduates to examine whether such accurate knowledge is acquired from learning prices in the new currency. The results show fast learning of prices of duration of cellular phone…

A family of integrals over infinite intervals appears frequently in the statistical literature on non-parametric regression. This note presents two simple transform methods, based on beta function and Parseval identity, to explicitly evaluate these integrals. These methods will benefit researchers and practitioners working in non-parametric…

A common type of problem encountered in mathematics is optimizing nonlinear functions. Many popular algorithms that are currently available for finding nonlinear least squares estimators, a special class of nonlinear problems, are sometimes inadequate. They might not converge to an optimal value, or if they do, it could be to a local rather than…

Is it possible to learn the relation between 2 nonadjacent events? M. Pena, L. L. Bonatti, M. Nespor, and J. Mehler (2002) claimed this to be possible, but only in conditions suggesting the involvement of algebraic-like computations. The present article reports simulation studies and experimental data showing that the observations on which Pe?a et…

This article introduces a procedure for estimating reliability in which equivalent halves of a given test are systematically created and then administered a few days apart so that transient error can be included in the error calculus. The procedure not only estimates complete reliability (taking into account both specific-factor error and…

The author describes a card trick that failed when he tried it with the student chapter at his university. Computations show that the chance of this happening is about 1 in 25.

This article discusses prime numbers, defined as integers greater than 1 that are divisible only by only themselves and the number 1. A positive integer greater than 1 that is not a prime is called composite. The number 1 itself is considered neither prime nor composite. As the name suggests, prime numbers are one of the most basic but important…

The problem of rotating a matrix orthogonally to a best least squares fit with another matrix of the same order has a closed-form solution based on a singular value decomposition. The optimal rotation matrix is not necessarily rigid, but may also involve a reflection. In some applications, only rigid rotations are permitted. Gower (1976) has…