probability

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Probability

The relative likelihood of a particular outcome among all possible outcomes.

probability

the likelihood of a particular uncertain event occurring, measured on a scale from 0.0 (such an event is impossible) to 1.0 (such an event is certain to occur). People generally estimate probabilities on the basis of the relative frequency with which an event has occurred in the past, under given circumstances, and generalize from this past experience. In some circumstances it is easy to estimate the proportion of occasions on which an event occurs; for example, the probability of getting ‘heads’ when flipping a balanced coin is 0.5 because with such a coin in the long run we would get 50% ‘heads’ and 50% ‘tails’. In estimating probabilities in business situations, though, there may be no or only a few previous experiences that can be used to gauge the relative frequency of an event occurring. See also RISK AND UNCERTAINTY.
References in periodicals archive ?
Kearon et al, (16) demonstrated the utility of D-dimer testing alone in excluding PE in low pretest probability patients, however, that alone cannot be used to exclude PE in patients with moderate to high risk of developing PE.
It was found in the study that coronary CT angiogram based strategy was safe for the evaluation of acute pain chest presumably of cardiac origin with low and intermediate pretest probability of coronary artery disease.
Nonsurgical biopsy is also recommended when the patient's pretest probability and imaging test results are discordant, when a benign diagnosis requires specific medical treatment, or if a fully informed patient desires proof of diagnosis prior to surgery.
This is important because the predictive value of the exercise stress test depends on the pretest probability of disease and the population at risk (2).
Tool for estimating pretest probability of coronary heart disease Variable Score Example: 52- year-old woman Age (male/female): -Under 40/under 50 3 -40 to 50/50 to 64 6 6 -55 or older/65 or older 9 Estrogen status positive (F) -3 -3 Estrogen status negative (F) 3 Angina history typical * 5 Angina history atypical 3 Angina history nonanginal 1 1 Diabetes 2 2 Hyperlipidemia 1 1 Hypertension 1 Smoking (any) 1 First-degree family history 1 1 of coronary artery disease Obesity (BMI >27 kg/[m.
Using electronic records and chart review, they sought to identify differences in the use of stress testing based on patient demographics and comorbidities, pretest probability of coronary artery disease, and house staff coverage.
4) An understanding of the patient population, patient pretest probability of CAD, Bayes' theorem, and the risk, benefits and limitations of each technology will enable the medical imaging professional to assist clinicians with test selection.
In their study, 3%, 17% and 75% of the patients with low, mode and high pretest probability, respectively, had DVT.
A negative ultrasound with a likely pretest probability of DVT indicates the need for repeat imaging.
Because a number of situations other than DVT and PE can elevate serum levels of d-dimer Table IIa scoring method using a clinical assessment model to determine pretest probability of DVT and PE has been useful in the diagnostic approach.

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