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  2. Cross-correlation - Wikipedia

    en.wikipedia.org/wiki/Cross-correlation

    [12] [13] [clarification needed] After calculating the cross-correlation between the two signals, the maximum (or minimum if the signals are negatively correlated) of the cross-correlation function indicates the point in time where the signals are best aligned; i.e., the time delay between the two signals is determined by the argument of the ...

  3. Negative relationship - Wikipedia

    en.wikipedia.org/wiki/Negative_relationship

    Negative correlation can be seen geometrically when two normalized random vectors are viewed as points on a sphere, and the correlation between them is the cosine of the circular arc of separation of the points on a great circle of the sphere. [1] When this arc is more than a quarter-circle (θ > π/2), then the cosine is negative.

  4. Lucas critique - Wikipedia

    en.wikipedia.org/wiki/Lucas_critique

    The Lucas critique is, in essence, a negative result. It tells economists, primarily, how not to do economic analyses. The Lucas critique suggests that if we want to predict the effect of a policy experiment, we should model the "deep parameters" (relating to preferences , technology , and resource constraints ) that are assumed to govern ...

  5. Berkson's paradox - Wikipedia

    en.wikipedia.org/wiki/Berkson's_paradox

    However, an individual who does not eat at any location where both are bad observes only the distribution on the bottom graph, which appears to show a negative correlation. The most common example of Berkson's paradox is a false observation of a negative correlation between two desirable traits, i.e., that members of a population which have ...

  6. Simpson's paradox - Wikipedia

    en.wikipedia.org/wiki/Simpson's_paradox

    Visualization of Simpson's paradox on data resembling real-world variability indicates that risk of misjudgment of true causal relationship can be hard to spot. 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.

  7. Correlation - Wikipedia

    en.wikipedia.org/wiki/Correlation

    Example scatterplots of various datasets with various correlation coefficients. The most familiar measure of dependence between two quantities is the Pearson product-moment correlation coefficient (PPMCC), or "Pearson's correlation coefficient", commonly called simply "the correlation coefficient".

  8. List of probability distributions - Wikipedia

    en.wikipedia.org/wiki/List_of_probability...

    The Dirac delta function, although not strictly a probability distribution, is a limiting form of many continuous probability functions. It represents a discrete probability distribution concentrated at 0 — a degenerate distribution — it is a Distribution (mathematics) in the generalized function sense; but the notation treats it as if it ...

  9. Correlation does not imply causation - Wikipedia

    en.wikipedia.org/wiki/Correlation_does_not_imply...

    If in fact a negative correlation exists between abuse and academic performance, researchers could potentially use this knowledge of a statistical correlation to make predictions about children outside the study who experience abuse even though the study failed to provide causal evidence that abuse decreases academic performance. [19]