The tested data are the minimum and maximum values. The cochrans c test cochran 1941 is one of the tests developed to identify and study the homogeneity of a series of variances bartletts test, brownforsythe, levene or hartley in particular. This behavior was measured for 20 workers on monday, wednesday and friday during one week in march, as shown in figure 1 where 1. In proficiency testing, john mandels k consistency statistic has been used specifically, the astm e691 standard to identify laboratories with excessively large variances the iso 5725 standard proposes cochrans variance outlier test as. These outcome variables have been measured on the same people or other statistical units. Using the grubbs and cochran tests to identify outliers. The result is a probality that indicates that the data belongs to the core population. Cochrans q test is an extension of the mcnemar test to a situation where there are more than two matched samples. Pvalues and cdf statistics are not currently computed for the twosided case note. The cochranarmitage test allows to test if a series of proportions, can be considered as varying linearly with an ordinal or continuous score variable. Cochranmantelhaenszel test english to spanish medical. If the investigated sample has some other, especially assymmetric distribution e. If x is the score variable, the statistic that is computed to test for the linearity is given by. Cochrans q is also considered to be a special case of the.
Workers at a large plant generally show two types of behavior. Are the variances homogeneous or is the highest variance different from the others. Cochrans test was developed to answer a specific question. Cochran s q is also considered to be a special case of the. Grubbs test this test detects outliers from normal distributions. The cochranmantelhaenszel cmh test compares two groups on a binary response, adjusting for control variables. Spss cochran q test is a procedure for testing if the proportions of 3 or more dichotomous variables are equal in some population. The principal of some university wants to know whether three examns are equally difficult. Essentially, the cmh test examines the weighted association of a set of 2 \\times\ 2 tables. The cochran mantelhaenszel cmh test compares two groups on a binary response, adjusting for control variables. The initial data are represented as a series of k 2x2 contingency table s, where k is the number of strata. Its always a good idea to take a quick look at what the data look like before proceeding to any statistical tests.