Statistical Glossary Robust Filter: A robust filter is a filter that is not sensitive to input noise values with extremely large magnitude (e.g. those arising due to anomalous measurement errors. The median filter is an example of a robust filter. Linear filters are not robust - their output may be...
View Full DescriptionRoot Mean Square: Root mean square (RMS) of a set of values xi, i=1,...N is the square root of the mean of the squares of the values: RMS is a statistical measure of departure from the null value. Browse Other Glossary Entries
View Full DescriptionRandom Numbers: Random numbers are the numbers produced by a truly random mechanism (in contrast to pseudo-random numbers ). For example, random numbers with a good degree of randomness may be produced by tossing a coin, recording "0" or "1" (instead of "head" or "tail"), and converting the sequence of...
View Full DescriptionReproducibility: Reproducibility is the variation of outcomes of an experiment carried out in conditions varying within a typical range, e.g. when measurement is carried out by the same device by different operators, in different laboratories, etc. For example, reproducibility of measurements of mechanical scales is the variation of weight values...
View Full DescriptionReplication: In statistics, replication is repetition of an experiment or observation in the same or similar conditions. Replication is important because it adds information about the reliability of the conclusions or estimates to be drawn from the data. The statistical methods that assess that reliability rely on replication. For example,...
View Full DescriptionRepeatability: Repeatability is the variation of outcomes of an experiment carried out in the same conditions, e.g. by the same operator, in the same laboratory. For example, repeatability of measurements of precise mechanical scales is the variation of weight values reported for a given constant mass by the same person,...
View Full DescriptionReplicate: A replicate is the outcome of an experiment or observation obtained in course of its replication . In applied statistics, a set of replicates obtained in a series of replications of the experiment or observations is considered as a sample from a much bigger population. This creates the logical...
View Full DescriptionReliability (in Survey Analysis): In survey analysis, e.g. in psychometrics , reliability is a measure of reproducibility of the survey instrument or test. In other words, reliability is a measure of precision - i.e. it describes the random error of the survey instrument. There are several types of reliability: test-retest...
View Full DescriptionReliability: Reliability characterises the capability of a device, unit, procedure to perform without fault. Reliability is quantified in terms of probability. This probability is related either to an elementary act or to an interval of time or another continuous variable. Because the probability of failure is normally a small fraction,...
View Full DescriptionRegression Trees: Regression trees is one of the CART techniques. The main distinction from classification trees (another CART technique) is that the dependent variable is continuous. See also this introductory text , this book Browse Other Glossary Entries
View Full DescriptionRectangular Filter: The rectangular filter is the simplest linear filter ; it is usually used as a smoother . The output of the rectangular filter at the time moment is the arithmetic mean of the input values corresponding to the moments of time close to : where is the output...
View Full DescriptionRecursive Filter: In recursive filters , the output at the moment is a function of the output values at the previous moments and, probably, of the input values. A major advantage of recursive filters over nonrecursive filters is that they are computationally simpler. For example, for any recursive linear filter...
View Full DescriptionRandom Error: The random error is the fluctuating part of the overall error that varies from measurement to measurement. Normally, the random error is defined as the deviation of the total error from its mean value. An example of random error is putting the same weight on an electronic scales...
View Full DescriptionQueuing Process: Queuing process is a class of random process es describing phenomena of queue formation. The term "queue" here is an abstract entity, which reflects the most common features of various types of real-life queues: traffic jams, queues to football matches, queue of e-mail messages on a server which...
View Full DescriptionProportional Hazard Model: Proportional hazard model is a generic term for models (particularly survival models in medicine) that have the form where L is the hazard function or hazard rate, {xi} are covariates, {bi} are coefficients of the model - effects of the corresponding covariates, and h(t) gives the effect...
View Full DescriptionStatistical Glossary Power Spectrum: The power spectrum of a stationary random process or a stationary time series is the average of the square of the amplitude of the Fourier spectrum : where is the amplitude spectrum of the realization of the random process ; is the operator of averaging over...
View Full DescriptionPsychometrics: Psychometrics or psychological testing is concerned with quantification (measurement) of human characteristics, behavior, performance, health, etc., as well as with design and analysis of studies based on such measurements. An example of the problems being solved in psychometrics is the measurement of intelligence via "IQ" scores. Statistical methods are...
View Full DescriptionStatistical Glossary Psychological Testing: See psychometrics . Browse Other Glossary Entries
View Full DescriptionStatistical Glossary Quadratic Mean: The quadratic mean is a special case of the power mean statistics , corresponding to the value of the parameter. The quadratic mean is a synonym of root mean square . The quadratic mean is used as a measure of "effective magnitude" of a set of...
View Full DescriptionStatistical Glossary Pseudo-Random Numbers: Pseudo-random numbers are produced by recursive algorithms - i.e. the current number is calculated from one or a greater number of previous numbers. Thus, strictly speaking, the pseudo-random numbers are deterministic, not random. On the other hand, in many respects pseudo-random numbers behave like truly random...
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