Quotient test

RAST quotient (test serum versus cord blood)... 

The Intelligence Quotient Tests for preschool children, school children and adults such as Stanford-Binet, Wechsler group tests, etc. 

In Case a, only the standard deviation estimated from the experimental data for the test sample is needed, which is then used to normalize the difference Xmean f - The quotient difference/.5 c, the so-called Student s f, is compared with the critical tc for a chosen confidence level and f n - 1. (Use Eq. 1.13.)... 

In the case of noncarcinogenic substances, there exists a threshold this is an exposure with a dose below which there would not be adverse effect on the population that is exposed. This is the reference dose (RfD), and it is defined as the daily exposure of a human population without appreciable effects during a lifetime. The RfD value is calculated by dividing the no observed effect level (NOEL) by uncertainty factors. When NOEL is unknown, the lowest observed effect level (LOEL) is used. NOEL and LOEL are usually obtained in animal studies. The main uncertainty factor, usually tenfold, used to calculate the RfD are the following the variations in interspecies (from animal test to human), presence of sensitive individuals (child and old people), extrapolation from subchronic to chronic, and the use of LOEL instead of NOEL. Noncancer risk is assessed through the comparison of the dose exposed calculated in the exposure assessment and the RfD. The quotient between both, called in some studies as hazard quotient, is commonly calculated (Eq. 2). According to this equation, population with quotient >1 will be at risk to develop some specific effect related to the contaminant of concern. 

We form a quotient when dividing one thing by another. We meet the word frequently when discussing a person s IQ, their intelligence quotient, which we define as (a person s score in an intelligence test 4- the average score) x 100. 

Finally, a measure of lack of fit using a PCs can be defined using the sum of the squared errors (SSE) from the test set, flSSETEST = Latest 2 (prediction sum of squares). Here, 2 stands for the sum of squared matrix elements. This measure can be related to the overall sum of squares of the data from the test set, SStest = -Xtest 2- The quotient of both measures is between 0 and 1. Subtraction from 1 gives a measure of the quality of fit or explained variance for a fixed number of a PCs ... 

The fraction of the analyte in the test sample. The mass fraction is a dimensionless number. However, the mass fraction is usually reported as a quotient of two mass-units or mass-volume. 

The F test tells us whether two standard deviations are "significantly different from each other. F is the quotient of the squares of the standard deviations ... 

Some investigators believe that the best course to follow in scratch hardness determination is to find the tangential force acting on the surface of material under test required to obtain a scratch of width b. In this case, hardness is expressed as the ratio of that force to the scratch cross-section or a magnitude proportional to it, or else as a quotient of the work necessary to produce the scratch and its volume. Proponents of this method (Yushkin, 1971) consider that scratch hardness tests in the present form play only a marginal role. Unlike Shreyner (1949), who contended that the results obtained under these methods are less accurate than those for mineral-bymineral scratch after Mohs, they accept that these tests have certain usefulness, but only of a complementary nature. The differences of opinion arise from the different approach to the question of accuracy of the method of determination itself, since as can readily be proved, a strict relationship exists between hardness defined as the ratio of load P to square of... 

The association between mean SQG quotients and toxic effects measured in the test batteries were not as clear for sites that yielded moderate SED-TOX scores. Indeed, mean SQG quotients ranged from 0.21 to 76.1 at these sites, indicating a wide range of contamination levels in the moderately toxic sediments. A variety of scenarios may explain this lack of correspondence for sediments falling into the moderate class of hazard potential, for example (1) toxicity may have occurred in sediments with low mean SQG quotients due to the potential effects of unmeasured contaminants or potentially toxic substances such as ammonia, butyl tin, and sulphur, which are not accounted for with SQGs (2) some contaminants may not have been present in bio-available forms (e.g. complexation with sediment particles, inorganic... 

The condition of variance homogeneity can be proven with the help of statistical tests (/- -test for quotient of variances at the lower and upper end of the calibration range, or better, in the case of rij>5 by using the Bartlett-test, which includes all of the variances in the calibration range). If variance homogeneity is violated, a weighted least squares regression (WLS) should be used. 

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