Effects of the contingency for submission of homework assignments on the probability of assignment submission and on quiz grades were assessed in an undergraduate psychology course. Under an alternating treatments design, each student was assigned to a points condition for 5 of 10 quiz-related homework assignments corresponding to textbook…

Purpose: This study examined the relation of dual and single sensory impairments, within the context of cognitive function, by using the framework of everyday competence in terms of the probability of difficulty with specific personal and instrumental activities of daily living (ADLs and IADLs, respectively). Design and Methods: The Longitudinal…

Objective: To examine whether children with substantiated maltreatment reports between 4 and 8 years of age differ from children with unsubstantiated reports on any of 10 behavioral and developmental outcomes. Method: Longitudinal data from 806 children and their adult caregivers collected in four US study sites were pooled and analyzed using…

Using data from 13 liberal arts colleges, we test for a preference for men in the college admissions process. We find that gender does matter, but in a complex way. Men do appear to be given preference as college applicant pools become more female. Consistent with this pattern, we find clear evidence of a preference for men in historically female…

This study examined the relationship between school tobacco policies and tobacco use prevalence among school personnel. Two subsets of schools were identified in Bihar, India: Federal schools (with a tobacco policy), and State schools (without a tobacco policy). Stratified probability samples of 50 schools each were selected. The survey was…

It is very well known that the Cauchy-Schwarz inequality is an important property shared by all inner product spaces and the inner product induces a norm on the space. A proof of the Cauchy-Schwarz inequality for real inner product spaces exists, which does not employ the homogeneous property of the inner product. However, it is shown that a real…

Tables for selecting sample size in correlation studies are presented. Some of the tables allow selection of sample size so that r (or r[squared], depending on the statistic the researcher plans to interpret) will be within a target interval around the population parameter with probability 0.95. The intervals are [plus or minus] 0.05, [plus or…

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.

Objective:: The prevalence of childhood sexual abuse among Latino adult men who have sex with men who live in the US was estimated because a history of childhood sexual abuse increases HIV sexual risk behaviors and other negative health outcomes in adulthood. Method:: The Urban Men's Health Study is a random-digit telephone probability survey of…

Consequential conditionals are defined as "if P then Q" statements, where P is an action, and Q a predicted outcome of this action, which is either desirable or undesirable to the agent. Experiment 1 shows that desirable (viz. undesirable) outcomes invite an inference to the truth (viz. falsity) of their antecedent. Experiment 2 shows that the…

The ability to derive predictions for the outcomes of potential actions from observational data is one of the hallmarks of true causal reasoning. We present four learning experiments with deterministic and probabilistic data showing that people indeed make different predictions from causal models, whose parameters were learned in a purely…

The present study investigated the influence of acoustical characteristics on the implicit learning of statistical regularities (transition probabilities) in sequences of musical timbres. The sequences were constructed in such a way that the acoustical dissimilarities between timbres potentially created segmentations that either supported (S1) or…

This article introduces the concept of a prediction interval in a gambling context.

Rolling dice and tossing coins can still be used to teach probability even if students know (or think they know) what happens in these experiments. This article considers many simple variations of these experiments which are interesting, potentially enjoyable and challenging. Using these variations can cause students (and teachers) to think again…

Pigeons pecked left versus right keys contingent upon the color presented at 1 of those locations. Spatial-response latencies were shorter when the color appeared at the same location as the required response than at the opposite location. This Simon effect occurred when the stimulus on the alternative key was constant, varied from trial to trial,…