Technical characteristics of the peabody individual achievement test as a function of item arrangement and basal and ceiling rules

The effects that item order and basal and ceiling rules have on test means, variances, and internal consistency estimates for the PIAT mathematics and reading recognition subtests were examined. Seven items on the math subtest and one item on the reading recognition subtest were significantly easier or harder than their test placement indicated. The use of basal and ceiling rules had a pronounced effect on the means, variances, and reliabilities on the multiple choice math subtest, while the rules' effects on the reading recognition subtests were minor. Item order also affected scores on the math subtest.     

"Science in a democracy": the contested status of vaccination in the Progressive Era and the 1920s

In the first decades of the twentieth century, a heterogeneous assortment of groups and individuals articulated scientific, political, and philosophical objections to vaccination. They engaged in an ongoing battle for public opinion with medical and scientific elites, who responded with their own counterpropaganda. These ideological struggles reflected fear that scientific advances were being put to coercive uses and that institutions of the state and civil society were increasingly expanding into previously private realms of decision making, especially child rearing. This essay analyzes the motivations and tactics of antivaccination activists and situates their actions within the scientific and social climate of the Progressive Era and the 1920s. Their actions reveal how citizens of varied ideological persuasions, activists and nonactivists alike, viewed scientific knowledge during a period of swift and unsettling change, when the application of biologic products seemed to hold peril as well as promise.     

The CS− effect in simple conditioning and stimulus selection during development

Changes in affect toward a particular stimulus can take place very rapidly through Pavlovian conditioning, if presentation of the conditioned stimulus (CS+) paired with the unconditioned stimulus (US) is accompanied by presentation of a “CS?,” another value of the same dimension as the CS+ but not paired with a US. This effect has considerable generality. It has been observed in terms of both olfactory and visual CSs, in terms of appetitive as well as aversive conditioning, and for adult as well as infant rats. The CS? effect has seemed especially important for infants, which may be related to the general tendency for infants to exhibit less stimulus selection than older animals. Finally, the CS? effect has enabled the development of a simple test of short-term retention that can quite effectively assess memory for either incidental or target events. These tests so far have indicated a clear ontogenetic decrease in rate of forgetting over short intervals, corresponding to the well-known development-related decrease in forgetting over long intervals (infantile amnesia). The tests also have shown that short-term forgetting of intentional and target events is surprisingly similar, with some indication of more rapid forgetting for the incidental events. Alternative interpretations of the CS? effect and some preliminary tests of these interpretations are discussed.     

Using an R shiny to enhance the learning experience of confidence intervals

Many students find understanding confidence intervals difficult, especially because of the amalgamation of concepts such as confidence levels, standard error, point estimates and sample sizes. An R Shiny application was created to assist the learning process of confidence intervals using graphics and data from the US National Basketball Association.     

Predicting vertical ground reaction force during running using novel piezoresponsive sensors and accelerometry

ABSTRACT

Running is a common exercise with numerous health benefits. Vertical ground reaction force (vGRF) influences running injury risk and running performance. Measurement of vGRF during running is now primarily constrained to a laboratory setting. The purpose of this study was to evaluate a new approach to measuring vGRF during running. This approach can be used outside of the laboratory and involves running shoes instrumented with novel piezoresponsive sensors and a standard accelerometer. Thirty-one individuals ran at three different speeds on a force-instrumented treadmill while wearing the instrumented running shoes. vGRF was predicted using data collected from the instrumented shoes, and predicted vGRF were compared to vGRF measured via the treadmill. Per cent error of the resulting predictions varied depending upon the predicted vGRF characteristic. Per cent error was relatively low for predicted vGRF impulse (2–7%), active peak vGRF (3–7%), and ground contact time (3–6%), but relatively high for predicted vGRF load rates (22–29%). These errors should decrease with future iterations of the instrumented shoes and collection of additional data from a more diverse sample. The novel technology described herein might become a feasible way to collect large amounts of vGRF data outside of the traditional biomechanics laboratory.