This study investigated the development of the many-to-one counting strategy in 4- year-old children. In the first experiment, 52 children participated. Their development with respect to two kinds of tasks, a hidden-items task and a needed-items task, was studied over four sessions. Children (n = 28) who accurately used the many-to-one strategy in…

The paper presents a study of novice difficulties with range conceptions in loop design. CS2 students were asked to solve four related enumeration tasks, which required various loop boundary specifications. The student solutions varied considerably in conciseness and efficiency. The solution diversity reveals significant differences in range…

This study compared nonverbal numerical processing in 6-year-olds with that in nonhuman animals using a numerical bisection task. In the study, 16 children were trained on a delayed match-to-sample paradigm to match exemplars of two anchor numerosities. Children were then required to indicate whether a sample intermediate to the anchor values was…

Recent studies using a violation-of-expectation task suggest that preverbal infants are capable of recognizing basic arithmetical operations involving visual objects. There is still debate, however, over whether their performance is based on any expectation of the arithmetical operations, or on a general perceptual tendency to prefer visually…

In this study, we use children's prior knowledge to support their development of cardinality understanding, based on Bermejo's (1996) model of cardinality understanding and on the distinction between cardinality (the number of items in a set is represented by a number-word) and the cardinality principle (the last number-word used in counting…

Two new tests for a model for the response times on pure speed tests by Rasch (1960) are proposed. The model is based on the assumption that the test response times are approximately gamma distributed, with known index parameters and unknown rate parameters. The rate parameters are decomposed in a subject ability parameter and a test difficulty…

This article proposes a general latent variable approach to discrete-time survival analysis of nonrepeatable events such as onset of drug use. It is shown how the survival analysis can be formulated as a generalized latent class analysis of event history indicators. The latent class analysis can use covariates and can be combined with the joint…

In this work, we present an algorithm for computing logarithms of positive real numbers, that bears structural resemblance to the elementary school algorithm of long division. Using this algorithm, we can compute successive digits of a logarithm using a 4-operation pocket calculator. The algorithm makes no use of Taylor series or calculus, but…

The concept of congruence between person and occupation lies at the core of Holland's (1997) theory of career types. The C index is arguably the best available method for comparing the congruence of two Holland code profiles. The C index reflects the theorized hexagonal structure of the Holland RIASEC model, is sensitive to code ordering, and is…

R. Rosenthal and D. B. Rubin (2003) proposed an effect size, r-sub(equivalent), to be used when (a) only sample size and p values are known for a study, (b) there are no generally accepted effect size indicators, or (c) sample sizes are so small or the data so non-normal that the directly computed effect sizes would be more misleading than the…

The GGUM2004 computer program estimates parameters for a family of unidimensional unfolding item response theory (IRT) models. These unfolding IRT models predict higher item scores to the extent that a respondent is located close to an item on an underlying latent continuum. This prediction is often consistent with responses to traditional…

In the past, juvenile gang researchers have focused primarily on the characteristics of gangs and the prevalence of gangs in communities and schools. One of the greatest limitations of this research, however, surrounds the lack of agreement on the definition of a gang and, consequently, the prevalence of gangs in the community and in schools. In…

In this study we investigated the variability, frequency, efficiency, and adaptiveness of young children's strategy use in the domain of simple addition by means of the choice/no-choice method. Seventy-seven beginning second-graders, divided in 3 groups according to general mathematical ability, solved a series of 25 simple additions in 3…

Students are asked to analyze a photo of a beer stein, computing volumes and areas based on the photo.

This article describes how the concept of "key idea" can be used in high school geometry to connect students' informal explorations with rigorous mathematical proof. (Contains 6 figures.)