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  2. Systematic code - Wikipedia

    en.wikipedia.org/wiki/Systematic_code

    Systematic codes have the advantage that the parity data can simply be appended to the source block, and receivers do not need to recover the original source symbols if received correctly – this is useful for example if error-correction coding is combined with a hash function for quickly determining the correctness of the received source ...

  3. Accuracy and precision - Wikipedia

    en.wikipedia.org/wiki/Accuracy_and_precision

    While precision is a description of random errors (a measure of statistical variability), accuracy has two different definitions: More commonly, a description of systematic errors (a measure of statistical bias of a given measure of central tendency, such as the mean). In this definition of "accuracy", the concept is independent of "precision ...

  4. Bias (statistics) - Wikipedia

    en.wikipedia.org/wiki/Bias_(statistics)

    In educational measurement, bias is defined as "Systematic errors in test content, test administration, and/or scoring procedures that can cause some test takers to get either lower or higher scores than their true ability would merit." [16] The source of the bias is irrelevant to the trait the test is intended to measure.

  5. Convolutional code - Wikipedia

    en.wikipedia.org/wiki/Convolutional_code

    Convolutional codes can be systematic and non-systematic: systematic repeats the structure of the message before encoding; non-systematic changes the initial structure; Non-systematic convolutional codes are more popular due to better noise immunity. It relates to the free distance of the convolutional code. [6]

  6. Propagation of uncertainty - Wikipedia

    en.wikipedia.org/wiki/Propagation_of_uncertainty

    Any non-linear differentiable function, (,), of two variables, and , can be expanded as + +. If we take the variance on both sides and use the formula [11] for the variance of a linear combination of variables ⁡ (+) = ⁡ + ⁡ + ⁡ (,), then we obtain | | + | | +, where is the standard deviation of the function , is the standard deviation of , is the standard deviation of and = is the ...

  7. Bias of an estimator - Wikipedia

    en.wikipedia.org/wiki/Bias_of_an_estimator

    The theory of median-unbiased estimators was revived by George W. Brown in 1947: [8]. An estimate of a one-dimensional parameter θ will be said to be median-unbiased, if, for fixed θ, the median of the distribution of the estimate is at the value θ; i.e., the estimate underestimates just as often as it overestimates.

  8. Sampling bias - Wikipedia

    en.wikipedia.org/wiki/Sampling_bias

    It results in a biased sample [1] of a population (or non-human factors) in which all individuals, or instances, were not equally likely to have been selected. [2] If this is not accounted for, results can be erroneously attributed to the phenomenon under study rather than to the method of sampling .

  9. Mathematics - Wikipedia

    en.wikipedia.org/wiki/Mathematics

    There is no general consensus about the definition of mathematics or its epistemological status—that is, its place inside knowledge. A great many professional mathematicians take no interest in a definition of mathematics, or consider it undefinable. There is not even consensus on whether mathematics is an art or a science.