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ABX Test
An ABX test is a method of comparing two choices of sensory stimuli to identify detectable differences between them. A subject is presented with two known samples (sample , the first reference, and sample , the second reference) followed by one unknown sample that is randomly selected from either A or B. The subject is then required to identify X as either A or B. If X cannot be identified reliably with a low p-value in a predetermined number of trials, then the null hypothesis cannot be rejected and it cannot be proven that there is a perceptible difference between A and B. ABX tests can easily be performed as double-blind trials, eliminating any possible unconscious influence from the researcher or the test supervisor. Because samples A and B are provided just prior to sample X, the difference does not have to be discerned from assumption based on long-term memory or past experience. Thus, the ABX test answers whether or not, under ideal circumstances, a perceptual difference can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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P-value
In null-hypothesis significance testing, the ''p''-value is the probability of obtaining test results at least as extreme as the result actually observed, under the assumption that the null hypothesis is correct. A very small ''p''-value means that such an extreme observed outcome would be very unlikely under the null hypothesis. Reporting ''p''-values of statistical tests is common practice in academic publications of many quantitative fields. Since the precise meaning of ''p''-value is hard to grasp, misuse is widespread and has been a major topic in metascience. Basic concepts In statistics, every conjecture concerning the unknown probability distribution of a collection of random variables representing the observed data X in some study is called a ''statistical hypothesis''. If we state one hypothesis only and the aim of the statistical test is to see whether this hypothesis is tenable, but not to investigate other specific hypotheses, then such a test is called a null ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Experiment
An experiment is a procedure carried out to support or refute a hypothesis, or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when a particular factor is manipulated. Experiments vary greatly in goal and scale but always rely on repeatable procedure and logical analysis of the results. There also exist natural experimental studies. A child may carry out basic experiments to understand how things fall to the ground, while teams of scientists may take years of systematic investigation to advance their understanding of a phenomenon. Experiments and other types of hands-on activities are very important to student learning in the science classroom. Experiments can raise test scores and help a student become more engaged and interested in the material they are learning, especially when used over time. Experiments can vary from personal and informal natural comparisons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Triangle Testing
Discrimination testing is a technique employed in sensory analysis to determine whether there is a detectable difference among two or more products. The test uses a group of assessors (panellists) with a degree of training appropriate to the complexity of the test to discriminate from one product to another through one of a variety of experimental designs. Though useful, these tests typically do not quantify or describe any differences, requiring a more specifically trained panel under different study design to describe differences and assess significance of the difference. Statistical basis The statistical principle behind any discrimination test should be to reject a null hypothesis (H0) that states there is no detectable difference between two (or more) products. If there is sufficient evidence to reject H0 in favor of the alternative hypothesis, HA: There is a detectable difference, then a difference can be recorded. However, failure to reject H0 should not be assumed to be su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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MUSHRA
MUSHRA stands for Multiple Stimuli with Hidden Reference and Anchor and is a methodology for conducting a codec listening test to evaluate the perceived quality of the output from lossy audio compression algorithms. It is defined by ITU-R recommendation BS.1534-3. The MUSHRA methodology is recommended for assessing "intermediate audio quality". For very small audio impairments, RecommendatioITU-R BS.1116-3(ABC/HR) is recommended instead. The main advantage over the mean opinion score (MOS) methodology (which serves a similar purpose) is that MUSHRA requires fewer participants to obtain statistically significant results. This is because all codecs are presented at the same time, on the same samples, so that a paired t-test or a repeated measures analysis of variance Analysis of variance (ANOVA) is a collection of statistical models and their associated estimation procedures (such as the "variation" among and between groups) used to analyze the differences among means. ANOVA was d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Objective Difference Grade
In digital audio, the objective difference grade (ODG) is calculated by perceptual evaluation of the audio quality algorithm In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific problems or to perform a computation. Algorithms are used as specifications for performing ... specified in ITU BS.1387-1.( PEAQ) It corresponds to the subjective difference grade used in human-based audio tests.''Introduction to Digital Audio Coding and Standards'', by Marina Bosi and Richard E. Goldberg, Kluwer Academic Publishers (2002) . The ODG ranges from 0 to −4 and is defined as follows: References Further reading * * Digital audio {{radio-comm-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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PEAQ
Perceptual Evaluation of Audio Quality (PEAQ) is a standardized algorithm for objectively measuring perceived audio quality, developed in 1994-1998 by a joint venture of experts within Task Group 6Q of the International Telecommunication Union's Radiocommunication Sector ( ITU-R). It was originally released as ITU-R Recommendation BS.1387 in 1998 and last updated in 2001. It utilizes software to simulate perceptual properties of the human ear and then integrates multiple model output variables into a single metric. PEAQ characterizes the perceived audio quality as subjects would do in a listening test according to ITU-R BS.1116. PEAQ results principally model mean opinion scores that cover a scale from 1 (bad) to 5 (excellent). Motivation The need to conserve bandwidth has led to developments in the compression of the audio data to be transmitted. Various encoding methods remove both redundancy and perceptual irrelevancy in the audio signal so that the bit rate required to encode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Short-term Memory
Short-term memory (or "primary" or "active memory") is the capacity for holding a small amount of information in an active, readily available state for a short interval. For example, short-term memory holds a phone number that has just been recited. The duration of short-term memory (absent rehearsal or active maintenance) is estimated to be on the order of seconds. The commonly cited capacity of 7 items, found in Miller's Law, has been superseded by 4±1 items. In contrast, long-term memory holds information indefinitely. Short-term memory is not the same as working memory, which refers to structures and processes used for temporarily storing and manipulating information. Stores The idea of separate memories for short-term and long-term storage originated in the 19th century. A model of memory developed in the 1960s assumed that all memories are formed in one store and transfer to others store after a small period of time. This model is referred to as the "modal model", mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Tell (poker)
A tell in poker is a change in a player's behavior or demeanor that is claimed by some to give clues to that player's assessment of their hand. A player gains an advantage if they observe and understand the meaning of another player's tell, particularly if the tell is unconscious and reliable. Sometimes a player may fake a tell, hoping to induce their opponents to make poor judgments in response to the false tell. More often, people try to avoid giving out a tell, by maintaining a poker face regardless of how strong or weak their hand is. Examples A tell may be common to a class of players or unique to a single player. Some possible tells include leaning forward or back, placing chips with more or less force, fidgeting, doing chip tricks, displaying nervous tics or making any changes in one's breathing, tone of voice, facial expressions, direction of gaze or in one's actions with the cards, chips, cigarettes or drinks. An underlying rule to many tells is: "weak means strong, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Simpson's Paradox
Simpson's paradox is a phenomenon in probability and statistics in which a trend appears in several groups of data but disappears or reverses when the groups are combined. This result is often encountered in social-science and medical-science statistics, and is particularly problematic when frequency data are unduly given causal interpretations. Judea Pearl. ''Causality: Models, Reasoning, and Inference'', Cambridge University Press (2000, 2nd edition 2009). . The paradox can be resolved when confounding variables and causal relations are appropriately addressed in the statistical modeling. Simpson's paradox has been used to illustrate the kind of misleading results that the misuse of statistics can generate. Edward H. Simpson first described this phenomenon in a technical paper in 1951, but the statisticians Karl Pearson (in 1899) and Udny Yule (in 1903 ) had mentioned similar effects earlier. The name ''Simpson's paradox'' was introduced by Colin R. Blyth in 1972. It is also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Ipsative
In psychology, ipsative questionnaires (; from Latin: ''ipse'', 'of the self') are those where the sum of scale scores from each respondent adds to a constant value. Sometimes called a forced-choice scale, this measure contrasts Likert-type scales in which respondents score—often from 1 to 5—how much they agree with a given statement (see also norm-referenced test). In psychology While mean scores from Likert-type scales can be compared across individuals, scores from an ipsative measure cannot. To explain, if an individual was equally extroverted and conscientious and was assessed on a Likert-type scale, each trait would be evaluated singularly, i.e. respondents would see the item "I enjoy parties" and agree or disagree with it to whatever degree reflected their preferences. If the same traits were evaluated on an ipsative measure, respondents would be forced to choose between the two, i.e. a respondent would see the item "Which of these do you agree with more strongly? a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Fidelity
Fidelity is the quality of faithfulness or loyalty. Its original meaning regarded duty in a broader sense than the related concept of ''fealty''. Both derive from the Latin word ''fidēlis'', meaning "faithful or loyal". In the City of London financial markets it has traditionally been used in the sense encompassed in the motto "My word is my bond". Audio and electronics In audio, "fidelity" denotes how accurately a copy reproduces its source. In the 1950s, the terms " high fidelity" or "hi-fi" were popularized for equipment and recordings which exhibited more accurate sound reproduction. For example, a worn gramophone record will have a lower fidelity than one in good condition, and a recording made by a low budget record company in the early 20th century is likely to have significantly less audio fidelity than a good modern recording. Similarly in electronics, fidelity refers to the correspondence of the output signal to the input signal, rather than sound quality, as i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |