Fischer statistics

Fischer statistics (F) Fischer statistics (F) is the ratio between explained and unexplained variance for a given number of degree of freedom. The larger the F value the greater the probability that the QSAR equation is significant. The F values obtained for these QSAR models are from 17.622 to 283.714, which are statistically significant at the 95% level. 

Fischer statistics (F) Fischer statistics (F) is the ratio between explained... 

The utilization of Equation (1) is conditioned by its statistical quality. Usually, regressional equations are characterized by correlation coefficient Cr) and standard deviation Cs, These two parameters do not allow a complete analysis of the quality of equations. It is necessary to use also other criteria such as the values of F (Fischer statistics), t (Student statistics), and EV (explained variance), ... 

Lungarella et al. 1984). In a chronic-duration study in B6C3F, mice where exposure was to commercial hexane (51.5% M-hexanc) for 6 hours/day, 5 days a week for 2 years, a statistically significant treatment-related increase in hepatocellular neoplasms (adenoma and carcinoma) was observed among females exposed at 9,018 ppm (Bio/Dynamics 1995b), but not at 900 or 3,000 ppm. No increases were observed in male mice or in Fischer 344 rats of either sex exposed similarly in a parallel experiment (Bio/Dynamics 1995a). 

Statistical Methods. Means of treatment groups for plasma retention of BSP, plasma osmolality, total plasma protein concentration and urine flow rates were compared by students t test for independent sample means (17). Plasma enzyme activity data were converted to a quantal form and analyzed by the Fischer Exact Probability Test (18). Values greater than 2 standard deviations (P < 0.05) from the control value were chosen to indicate a positive response in treated fish. 

Fischer TP, Hilton DR, Zimmer MM, Shaw AM, Sharp ZD, Walker JA (2002) Subduction and recycling of nitrogen along the Central American margin. Science 297 1154-1157 Fitzsimons ICW, Harte B, Clark RM (2000) SIMS stable isotope measurement counting statistics and analytical precision, Min Mag 64 59-83... 

Formaldehyde has been shown to be carcinogenic in two strains of rats, resulting in squamous cell cancers of the nasal cavity after repeated inhalation of about 14 ppm. In one study, 51 of 117 male and 42 of 115 female Fischer 344 rats developed this tumor, but no nasal tumors were seen at 0 or 2 ppm. No other neoplasm was increased significantly. In a similar study of mice, this nasal tumor occurred in two male mice at 14.3 ppm. None of the excesses was statistically significant except for the high-exposure rats. °... 

Xu C, Barnes SE, Wu T, Fischer DA, DeLongchamp DM, Batteas JD, Beers KL (2006) Solution and surface gradients via micro fluidic confinement fabrication of a statistical copolymer brush composition gradient. Adv Mater 18 1427... 

Male and female Fischer 344 rats and B6C3Fi mice were fed di(2-ethylhexyl) phthalate for up to 13 weeks (David et al., 1999). In rats fed 12 500 ppm di(2-ethylhexyl) phthalate, there was an increase in hepatocyte replicative DNA s mthesis (measured after continuous bromodeoxyuridine administration (osmotic pump) for three days before sampling) after one week (but not after two or 13 weeks) and an increase in hepatic peroxisomal [3-oxidation activity after one, two and 13 weeks administration. In mice fed 10 000 and 17 500 ppm di(2-ethylhexyl) phthalate, there was no increase in hepatocyte replicative DNA synthesis (measured after continuous bromodeoxyuridine three days before sampling) after one, two or 13 weeks of administration, but there was an increase in hepatic peroxisomal 3-oxidation activity after one, two and 13 weeks administration. In mice fed 1000 ppm di(2-ethylhexyl) phthalate, there was no statistically significant increase in hepatic peroxisomal 13-oxidation activity after one, two or 13 weeks administration (bromodeoxyuridine labelling was not evaluated at this lower dietary concentration of di(2-ethylhexyl) phthalate). 

The molecule is twisting and bending around all of the time, and the conformation with the bracelet-shaped skeleton is just one of the possible conformations. The molecule probably spends very little of its time like this (just from a statistical point of view—this is one of many possible conformations), but this is the conformation that we will use to draw our Fischer projection. 

In order to assess the statistical significance of the model, a randomization trial procedure (called catScramble) derived from the Fischer method was performed. Results after scrambling affinity values showed that there is at least a 95% chance that the best model reports a true correlation between structural and biological data. 

In oral studies, the SOA was considered the upper alimentary tract and the forestomach, which were observed at necropsy. The statistical methods used were the Poly-k-test or Fischer exact test, as described by Piegorsch et al. (1997), Portier et al. (1989) and Gartetal. (1979). 

Bednorz-Muller theory Beer-Lambert law Bose-Einstein statistics Debye-Huckel theory Diels-Alder reaction Fermi-Dirac statistics Fischer-Tropsch effect Fisher-lohns hypothesis Flory-Huggins interaction Franck-Condon factor Friedel-Crafts reaction Geiger-Miiller effect... 

The distribution of a population s property can be introduced mathematically by the repartition function of a random variable. It is well known that the repartition function of a random variable X gives the probability of a property or event when it is smaller than or equal to the current value x. Indeed, the function that characterizes the density of probability of a random variable (X) gives current values between X and x -I- dx. This function is, in fact, the derivative of the repartition function (as indirectly shown here above by relation (5.16)). It is important to make sure that, for the characterization of a continuous random variable, the distribution function meets all the requirements. Among the numerous existing distribution functions, the normal distribution (N), the chi distribution (y ), the Student distribution (t) and the Fischer distribution are the most frequently used for statistical calculations. These different functions will be explained in the paragraphs below. 

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