Learning relative frequency distributions: Some perceptual and cognitive factors.

1973 ◽  
Vol 100 (1) ◽  
pp. 106-115
Author(s):  
Charles A. J. Vlek ◽  
Hans H. Werner
Keyword(s):  
Relative Frequency ◽  
Cognitive Factors ◽  
Frequency Distributions

Graphical presentation of distributions of risk in screening

2005 ◽  
Vol 12 (3) ◽  
pp. 155-160 ◽  
Author(s):  
J K Morris ◽  
N J Wald
Keyword(s):  
Relative Frequency ◽  
Gaussian Approximation ◽  
Gaussian Model ◽  
Likelihood Ratios ◽  
Frequency Distributions ◽  
Risk Estimates ◽  
Screening Performance ◽  
Log Likelihood ◽  
Standard Deviations ◽  
Screening Marker

Objective: The screening performance of tests involving multiple markers is usually presented visually as two Gaussian relative frequency distributions of risk, one curve relating to affected and the other to unaffected individuals. If the distribution of the underlying screening markers is approximately Gaussian, risk estimates based on the same markers will usually also be approximately Gaussian. However, this approximation sometimes fails. Here we examine the circumstances when this occurs. Setting: A theoretical statistical analysis. Methods: Hypothetical log Gaussian relative distributions of affected and unaffected individuals were generated for three antenatal screening markers for Down's syndrome. Log likelihood ratios were calculated for each marker value and plots of the relative frequency distributions were compared with plots of Gaussian distributions based on the means and standard deviations of these log likelihood ratios. Results: When the standard deviations of the distributions of a perfectly Gaussian screening marker are similar in affected and unaffected individuals, the distributions of risk estimates are also approximately Gaussian. If the standard deviations differ materially, incorrectly assuming that the distributions of the risk estimates are Gaussian creates a graphical anomaly in which the distributions of risk in affected and unaffected individuals plotted on a continuous risk scale intersect in two places. This is theoretically impossible. Plotting the risk distributions empirically reveals that all individuals have an estimated risk above a specified value. For individuals with more extreme marker values, the risk estimates reverse and increase instead of continuing to decrease. Conclusion: It is useful to check whether a Gaussian approximation for the distribution of risk estimates based on a screening marker is valid. If the value of the marker level at which risk reversal occurs lies within the set truncation limits, these may need to be reset, and a Gaussian model may be inappropriate to illustrate the risk distributions.

On the Relative-Frequency Interpretation of Finite Maximum-Entropy Distributions

1975 ◽  
Vol 7 (3) ◽  
pp. 325-347 ◽  
Author(s):  
T E Smith
Keyword(s):  
Maximum Entropy ◽  
Relative Frequency ◽  
Prior Information ◽  
Frequency Distributions ◽  
Frequency Interpretation ◽  
Maximum Entropy Distributions

This paper critically reexamines the Jaynes interpretation of finite maximum-entropy distributions as limits of the ‘most likely’ relative-frequency distributions consistent with any given prior information. It is shown that while this interpretation is valid in a number of cases, it fails to hold for many types of prior information. Given this limitation, a weaker form of the Jaynes interpretation is proposed which is shown to hold for a wider class of prior information.

Within-Response Force Variations Accompanying Differentiation of Duration in Rats

1977 ◽  
Vol 40 (3_suppl) ◽  
pp. 1271-1284 ◽  
Author(s):  
Stephen C. Fowler ◽  
Robert J. Filewich ◽  
Mark R. Leberer
Keyword(s):  
Relative Frequency ◽  
Response Duration ◽  
The Other ◽  
Force Sensing ◽  
Response Force ◽  
Individual Response ◽  
Frequency Distributions ◽  
Joint Force ◽  
Force Criterion ◽  
Water Reinforcer

By using a force-sensing isometric manipulandum, response force waveforms were recorded from rats performing a duration differentiation. For 2 rats exteroceptive cues were correlated with response force exceeding the force criterion and with attainment of the 1.60-sec. duration required for reinforcement. The other 3 rats received no exteroceptive support, the water reinforcer being delivered upon response termination. In the last phase of the experiment, reinforcement was contingent upon holding response force within a force “band” for a specified time. Relative frequency distributions of response duration indicated that differentiation of duration was more accurate in the presence of exteroceptive cues than in the absence of such stimuli. Spectral analysis of individual response waveforms indicated that rhythmic force oscillations (2 to 6 hz) predominated, despite the subjects' reliance on exteroceptive stimuli. Introduction of the joint force-band-duration contingency reduced but did not completely abolish the oscillations for both cued and uncued subjects. Over-all the results suggest that the rhythmic force variations observed here may be unselected or elicited components of the response rather than manifestations of a proprioceptive self-cueing process.

scholarly journals A new approach to quantify angles and time of changes-of-direction during soccer matches

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251292
Author(s):  
Tomohiro Kai ◽  
Shin Hirai ◽  
Yuhei Anbe ◽  
Yohei Takai
Keyword(s):  
Relative Frequency ◽  
Soccer Player ◽  
Soccer Players ◽  
Positioning System ◽  
New Approach ◽  
Frequency Distributions ◽  
Local Positioning System ◽  
Relative Frequency Distribution ◽  
The Difference ◽  
Coordinate Data

Background and aims Soccer players frequently perform change-of-directions (CODs) at various speeds during matches. However, tracking systems have shown limitations to measure these efforts. Therefore, the aim of the present study was to propose a new approach to measure CODs using a local positioning system (LPS), and clarify position-related difference in profile of CODs by using the approach. Methods The x- and y-coordinate data for each soccer player were measured with a local positioning system. Speed, acceleration, jerk, and direction of speed were derived from the coordinate data. Based on accelerations of above 2 m/s2, the onsets and ends of CODs derived from jerk were identified (COD duration). Changes of direction of speed (θCOD) were determined for the corresponding period. Six collegiate male soccer players performed CODs according to 13 set angles (0–180°; every 15°) so that differences between θCOD and set angle could be determined (Exp. 1). Relative frequency distributions of θCOD and number of CODs were determined in 79 collegiate and amateur male soccer players during 9 soccer matches (Exp. 2). Results In Exp. 1, θCOD was positively related to set angle (r = 0.99). Each θCOD was smaller than the corresponding set angle, and the difference became greater with increasing COD angle. In Exp. 2, The number of CODs in a match was 183 ± 39 across all positions. There were no significant position-related differences in the number of CODs. The duration of a COD was 0.89 ± 0.49 s across all positions. The relative frequency distribution of θCOD revealed that the number of CODs at 0–15° and 105–135° tended to be higher than those at other angles during soccer matches. Further, θCOD was affected by the speed at the onset of COD during soccer matches (Exp. 2). Conclusions The current findings demonstrate that θCOD derived from direction of speed and jerk may be a new indicator for evaluating COD during soccer matches.

scholarly journals Frequency at the syntax–discourse interface: A bidirectional study on fronting options in L1/L2 German and L1/L2 English

2018 ◽  
Vol 36 (1) ◽  
pp. 65-96 ◽  
Author(s):  
Holger Hopp ◽  
Joseph Bail ◽  
Carrie N. Jackson
Keyword(s):  
Second Language ◽  
High Frequency ◽  
Relative Frequency ◽  
Judgment Task ◽  
Structural Constraints ◽  
Frequency Distributions ◽  
Narrow Focus ◽  
Per Se ◽  
Discourse Interface ◽  
L1 English

The present study investigates whether second language (L2) speakers are sensitive to the information-structural constraints and frequency distributions at the syntax–discourse interface in the L2. L1-German–L2-English and L1-English–L2-German speakers completed a speeded naturalness judgment task. For sentences presented in broad or narrow-focus contexts, they judged the naturalness of fronted locative (LP) and temporal (TP) adverbial phrases and fronted objects in both English and German. English and German differ in the frequency with which they employ these constructions. With high-frequency fronted-LP and TP sentences, both the L2 English and L2 German speakers exhibited equivalent judgments as their L1 counterparts, in spite of differences in the perceived naturalness and relative frequency of these constructions in English vs. German. Like L1 speakers, L2 English and L2 German speakers also judged the less-frequent fronted objects as more natural in narrow-focus than broad-focus contexts, showing successful acquisition at the syntax–discourse interface. However, they judged fronted object sentences as more natural overall than their respective L1 counterparts in both English and German. Together, these findings suggest that convergence at the L2 syntax–discourse interface is possible per se, but that lower construction frequency in the input entails persistent overgeneralization of non-canonical options in the L2.

Relative Frequency Predicts Presence of Voice Disorders

ASHA Leader ◽  
2013 ◽  
Vol 18 (3) ◽  
pp. 31-31
Keyword(s):  
Relative Frequency ◽  
Voice Disorders

Relative Frequency Predicts Presence of Voice Disorders

Prospective Memory Development Across the Lifespan

2020 ◽  
Vol 25 (3) ◽  
pp. 162-173 ◽  
Author(s):  
Sascha Zuber ◽  
Matthias Kliegel
Keyword(s):  
Prospective Memory ◽  
Healthy Aging ◽  
Present Model ◽  
Current Knowledge ◽  
Well Being ◽  
The Elderly ◽  
Cognitive Factors ◽  
Everyday Functioning ◽  
Integrative Framework

Abstract. Prospective Memory (PM; i.e., the ability to remember to perform planned tasks) represents a key proxy of healthy aging, as it relates to older adults’ everyday functioning, autonomy, and personal well-being. The current review illustrates how PM performance develops across the lifespan and how multiple cognitive and non-cognitive factors influence this trajectory. Further, a new, integrative framework is presented, detailing how those processes interplay in retrieving and executing delayed intentions. Specifically, while most previous models have focused on memory processes, the present model focuses on the role of executive functioning in PM and its development across the lifespan. Finally, a practical outlook is presented, suggesting how the current knowledge can be applied in geriatrics and geropsychology to promote healthy aging by maintaining prospective abilities in the elderly.

Cognitive Factors Mediate the Relation Between Age and Flight Path Maintenance in General Aviation

2016 ◽  
Vol 6 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Kathleen Van Benthem ◽  
Chris M. Herdman
Keyword(s):  
Cognitive Functioning ◽  
Flight Path ◽  
General Aviation ◽  
Cognitive Factors ◽  
Pilot Performance ◽  
Pilot Error ◽  
Age Related ◽  
And Performance ◽  
Relationship Of ◽  
The Relationship

Abstract. Identifying pilot attributes associated with risk is important, especially in general aviation where pilot error is implicated in most accidents. This research examined the relationship of pilot age, expertise, and cognitive functioning to deviations from an ideal circuit trajectory. In all, 54 pilots, of varying age, flew a Cessna 172 simulator. Cognitive measures were obtained using the CogScreen-AE ( Kay, 1995 ). Older age and lower levels of expertise and cognitive functioning were associated with significantly greater flight path deviations. The relationship between age and performance was fully mediated by a cluster of cognitive factors: speed and working memory, visual attention, and cognitive flexibility. These findings add to the literature showing that age-related changes in cognition may impact pilot performance.

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