scholarly journals STUDI RANDOM ERROR PADA PENGUKURAN MIKROTREMOR SERTA IMPLIKASINYA TERHADAP PERHITUNGAN Vs30 DAN KETEBALAN SEDIMEN

Instrumentasi ◽  
2021 ◽  
Vol 45 (2) ◽  
pp. 175
Author(s):  
Ashar Muda Lubis ◽  
Muttaqin Muttaqin ◽  
Rida Samdara
Keyword(s):  
Methodology ◽  
2009 ◽  
Vol 5 (1) ◽  
pp. 3-6 ◽  
Author(s):  
Merton S. Krause

There is another important artifactual contributor to the apparent improvement of persons subjected to an experimental intervention which may be mistaken for regression toward the mean. This is the phenomenon of random error and extreme selection, which does not at all involve the population regression of posttest on pretest scores but involves a quite different and independent reversion of subjects’ scores toward the population mean. These two independent threats to the internal validity of intervention evaluation studies, however, can be detected and differentiated on the sample data of such studies.


Author(s):  
Emilio J Ruiz-Malagón ◽  
Santiago A Ruiz-Alias ◽  
Felipe García-Pinillos ◽  
Gabriel Delgado-García ◽  
Victor M Soto-Hermoso

Chest bands have been the most used device to monitor heart rate during running. However, some runners feel uncomfortable with the use of bands due to the friction and pressure exerted on the chest. Thus, the aim of this study was to determine if the photoplethysmography (PPG) system Polar Precision Prime used in the Polar Vantage M watch could replace chest bands (Polar V800-H10) to monitor heart rate with the same precision. A group of 37 people, middle-distance and long-distance professional runners, participated in this study. The submaximal speed was determined using 50% of the participants’ maximum speed in the height of their season. The Polar Vantage M reported high correlation ( r > 0.84) and high ICC (ICC > 0.86) when comparing its heart rate monitor with the Polar V800 synchronised with H10 chest strap during recording intervals of more than 2 min. The systematic bias and random error were very small (<1 bpm), especially for the 600 s recording interval (0.26 ± 5.10 bpm). Nevertheless, the error increased for 10 s (−5.13 ± 9.20 bpm), 20 s (−8.65 ± 12.60 bpm) and 30 s (−10.71 ± 14.99 bpm) time intervals. In conclusion, the PPG Polar Precision Prime included in the Polar Vantage M demonstrates that it could be a valid alternative to chest bands for monitoring heart rate while running, taking into account some usage considerations, good strap adjustment and an initial calibration time during the first 2–3 min.


1972 ◽  
Vol 31 (1) ◽  
pp. 131-140 ◽  
Author(s):  
Donald W. Zimmerman

The concepts of random error and reliability of measurements that are familiar in traditional theories based on the notions of “true values” and “errors” can be represented by a probability model having a simpler formal structure and fewer special assumptions about random sampling and independence of measurements. In this model formulas that relate observable events are derived from probability axioms and from primitive terms that refer to observable events, without an intermediate structure containing variances and correlations of “true” and “error” components of scores. While more economical in language and formalism, the model at the same time is more general than classical theories and applies to stochastic processes in which joint distributions of many dependent random variables are of interest. In addition, it clarifies some long-standing problems concerning “experimental independence” of measurements and the relation of sampling of individuals to sampling of measurements.


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