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  2. False positives and false negatives - Wikipedia

    en.wikipedia.org/wiki/False_positives_and_false...

    Despite the fact that the likelihood ratio in favor of the alternative hypothesis over the null is close to 100, if the hypothesis was implausible, with a prior probability of a real effect being 0.1, even the observation of p = 0.001 would have a false positive rate of 8 percent. It wouldn't even reach the 5 percent level.

  3. One- and two-tailed tests - Wikipedia

    en.wikipedia.org/wiki/One-_and_two-tailed_tests

    p-value of chi-squared distribution for different number of degrees of freedom. The p-value was introduced by Karl Pearson [6] in the Pearson's chi-squared test, where he defined P (original notation) as the probability that the statistic would be at or above a given level. This is a one-tailed definition, and the chi-squared distribution is ...

  4. p-value - Wikipedia

    en.wikipedia.org/wiki/P-value

    If we use the test statistic /, then under the null hypothesis is exactly 1 for two-sided p-value, and exactly / for one-sided left-tail p-value, and same for one-sided right-tail p-value. If we consider every outcome that has equal or lower probability than "3 heads 3 tails" as "at least as extreme", then the p -value is exactly 1 / 2 ...

  5. q-value (statistics) - Wikipedia

    en.wikipedia.org/wiki/Q-value_(statistics)

    If we control the pFDR to 0.05 by considering all genes with a q-value of less than 0.05 to be differentially expressed, then we expect 5% of the positive results to be false positives (e.g. 900 true positives, 45 false positives, 100 false negatives, 8,955 true negatives). This strategy enables one to obtain relatively low numbers of both ...

  6. 68–95–99.7 rule - Wikipedia

    en.wikipedia.org/wiki/68–95–99.7_rule

    Refined models should then be considered, e.g. by the introduction of stochastic volatility. In such discussions it is important to be aware of the problem of the gambler's fallacy , which states that a single observation of a rare event does not contradict that the event is in fact rare.

  7. False positive rate - Wikipedia

    en.wikipedia.org/wiki/False_positive_rate

    The false positive rate is calculated as the ratio between the number of negative events wrongly categorized as positive (false positives) and the total number of actual negative events (regardless of classification). The false positive rate (or "false alarm rate") usually refers to the expectancy of the false positive ratio.

  8. Necessity and sufficiency - Wikipedia

    en.wikipedia.org/wiki/Necessity_and_sufficiency

    The assertion that Q is necessary for P is colloquially equivalent to "P cannot be true unless Q is true" or "if Q is false, then P is false". [9] [1] By contraposition, this is the same thing as "whenever P is true, so is Q". The logical relation between P and Q is expressed as "if P, then Q" and denoted "P ⇒ Q" (P implies Q).

  9. Conditional probability distribution - Wikipedia

    en.wikipedia.org/wiki/Conditional_probability...

    Then the unconditional probability that = is 3/6 = 1/2 (since there are six possible rolls of the dice, of which three are even), whereas the probability that = conditional on = is 1/3 (since there are three possible prime number rolls—2, 3, and 5—of which one is even).