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In statistics, Levene's test is an inferential statistic used to assess the equality of variances for a variable calculated for two or more groups. [1] This test is used because some common statistical procedures assume that variances of the populations from which different samples are drawn are equal. Levene's test assesses this assumption.
The Duquenois reagent is used in the Rapid Modified Duquenois–Levine test (also known as the simple Rapid Duquenois Test), which is an established screening test for the presence of cannabis. The test was initially developed in the 1930s by the French medical biochemist Pierre Duquénois (1904–1986) and was adopted in the 1950s by the ...
Howard Levene (January 17, 1914 – July 2, 2003) [1] was an American statistician and geneticist. He received his Ph.D. from Columbia University in 1947, and joined the faculty there shortly thereafter. He remained on the faculty at Columbia, where he served as professor of mathematical statistics and genetics, until 1982.
The null hypothesis of this chi-squared test is homoscedasticity, and the alternative hypothesis would indicate heteroscedasticity. Since the Breusch–Pagan test is sensitive to departures from normality or small sample sizes, the Koenker–Bassett or 'generalized Breusch–Pagan' test is commonly used instead.
In statistics, an F-test of equality of variances is a test for the null hypothesis that two normal populations have the same variance.Notionally, any F-test can be regarded as a comparison of two variances, but the specific case being discussed in this article is that of two populations, where the test statistic used is the ratio of two sample variances. [1]
In statistics, Bartlett's test, named after Maurice Stevenson Bartlett, [1] is used to test homoscedasticity, that is, if multiple samples are from populations with equal variances. [2] Some statistical tests, such as the analysis of variance , assume that variances are equal across groups or samples, which can be checked with Bartlett's test.
Still, the result was quite impressive, with years-long stains lifting away almost without a trace. Writer Brittany Nims tested The Pink Stuff cleaning paste on years-old stainless steel cookware ...
Developed in 1940 by John W. Mauchly, [3] Mauchly's test of sphericity is a popular test to evaluate whether the sphericity assumption has been violated. The null hypothesis of sphericity and alternative hypothesis of non-sphericity in the above example can be mathematically written in terms of difference scores.