This paper examines the difference between mass and weight, which is discussed very early in most physics courses. Those who indulge in mathematical problems involving weights should know the difference. Mass is often defined as the amount of matter in an object. This usually means the sum of the masses of all the atoms that constitute that…

We use exogenous variation in Social Security payments created by the Social Security benefits notch to estimate how retirees' use of prescription medications responds to changes in their incomes. Using data from the 1993 Wave of the AHEAD, we obtain instrumental variables estimates of the income elasticity of prescription drug use that are…

National Assessment of Educational Progress (NAEP) shows a deficiency in U.S. students' mathematics performance and computation skills. The students using calculators in school classrooms result in lower math scores than students who never use them.

A 2-high-threshold signal detection (HTSDT) model, a mixture distribution (SON) model, and 2-highthreshold (HT) models with responses distributed over 1 or several response categories were fit to results of 6 experiments from 2 studies on associative recognition: R. Kelley and J. T. Wixted (2001) and A. P. Yonelinas (1997). HTSDT assumes that…

T. Trabasso and J. Bartolone (see record 2003-07955-016) used a computational model of narrative text comprehension to account for empirical findings. The authors show that the same predictions are obtained without running the model. This is caused by the model's computational setup, which leaves most of the model's input unchanged.

Given a set of urns, each filled with a mix of black chips and white chips, what is the probability of drawing a black chip from the last urn after some sequential random shifts of chips among the urns? The Total Probability Formula (TPF) is the common tool to solve such a problem. However, when the number of urns is more than two and the number…

This article examines how numerical intuition for prices develops after a major change in currency. University students in Portugal (Study 1) and Austria (Study 2) made price estimates for 40 different items from November 2001 to June 2002, surrounding the time at which these countries switched to the euro. Overall results are more in accordance…

The starting point for this discussion of error estimates is the fact that integrals that arise in Fourier series have properties that can be used to get improved bounds. This idea is extended to more general situations.

As the title says, this article considers the dog-on-the-beach problem from the perspective of the calculus of variations, making connections with the brachistochrone problem and Snell's law.

Do people tend to underestimate time when their attention is engaged? Studies supporting this idea have routinely confounded attentional manipulations with changes in other factors, such as response complexity and memory load. The aim of the present study was to obtain the first direct evidence that attentional engagement mediated by cortical…

Neater representations for variance are given for small sample sizes, especially for 3 and 4. With these representations, variance can be calculated without a calculator if sample sizes are small and observations are integers, and an upper bound for the standard deviation is immediate. Accessible proofs of lower and upper bounds are presented for…

This article illustrates that not all statistical software packages are correctly calculating a "p"-value for the classical "F" test comparison of two independent Normal variances. This is illustrated with a simple example, and the reasons why are discussed. Eight different software packages are considered.

The authors introduce subset conjunction as a classification rule by which an acceptable alternative must satisfy some minimum number of criteria. The rule subsumes conjunctive and disjunctive decision strategies as special cases. Subset conjunction can be represented in a binary-response model, for example, in a logistic regression, using only…

In hierarchical linear models we often find that group indicator variables at the cluster level are significant predictors for the regression slopes. When this is the case, the average relationship between the outcome and a key independent variable are different from group to group. In these settings, a question such as "what range of the…

The notion of an impact factor was first posited by Eugene Garfield (1972) to study the use, prestige, and status of scientific journals. The Institute for Scientific Information created the impact factor as a means to measure the number of times an "average article" published in a journal was cited over a particular time period ("The impact…