Statistics software

Similarity is often used as a general term to encompass either similarity or dissimilarity or both (see Section 6.4.3, on similarity measures, below). The terms "proximity" and distance are used in statistical software packages, but have not gained wide acceptance in the chemical literature. Similarity and dissimilarity can in principle lead to different rankings. 

TableCurve is available from Systat Software Inc., 501 Canal Boulevard, Suite E, Richmond, CA 94804-2028 (http //www.systat.com/products/tablecurve2d/). A free trial version of TableCurve is available at this web site. Systat offers other curvefitting and statistical software.

The linear regression calculations for a 2 factorial design are straightforward and can be done without the aid of a sophisticated statistical software package. To simplify the computations, factor levels are coded as +1 for the high level, and -1 for the low level. The relationship between a factor s coded level, Xf, and its actual value, Xf, is given as... 

B. P. Butler, M. G. Cox, S. L. R. Ellison, and W. A. Hardcastle, Statistics Software Qualification (Reference Data Sets), The Royal Society of Chemistry, ISBN 0-85404-422-1. 

The data from sensory evaluation and texture profile analysis of the jellies made with amidated pectin and sunflower pectin were subjected to Principal component analysis (PC) using the statistical software based on Jacobi method (Univac, 1973). The results of PC analysis are shown in figure 7. The plane of two principal components (F1,F2) explain 89,75 % of the variance contained in the original data. The attributes related with textural evaluation are highly correlated with the first principal component (Had.=0.95, Spr.=0.97, Che.=0.98, Gum.=0.95, Coe=0.98, HS=0.82 and SP=-0.93). As it could be expected, spreadability increases along the negative side of the axis unlike other textural parameters. 

The data were statistically analyzed using the SOLO Statistical System (BMDP Statistical Software, Inc., Los Angeles, CA) on a personal computer. Differences between groups were tested by the Mann-Whitney test or a paired t-test in cases where paired data sets were tested. Possible relationships were studied with (multiple) linear regression using least-square estimates. 

Both planar and curved surfaces can be fitted by statistical software packages like Statistica [1993]. In the general case, the 3-D calibration surface is given by... 

Wienke D, Wank U, Wagner M, Danzer K (1991) MULTIVAR, PLANEX, INTERLAB -from a collection of algorithms to an expert system Statistical software written from chemists for chemists. In Gmeling J (ed) Software development in chemistry 5, Springer, Berlin Heidelberg New York, p 113... 

Rosenberg MS, Adams DC, Gurevitch J (2000) Version 2 MetaWin statistical software for metaanalysis. Sinauer Associates, Sunderland, MA... 

For practical computation the software environment R is used. R is a powerful statistical software tool, it is freeware and can be downloaded at http //cran.r-project. org. Throughout the book we will present relevant R commands, and in Appendix 3 a brief introduction to R is given. An R-package chemometrics has been established it contains most of the data sets used in the examples and a number of newly written functions mentioned in this book. 

Hahn, GJ. (1985), More Intelligent Statistical Software and Statistical Expert Systems Future Directions, American Statistician, 39, 1-16. 

During the Western Project, a total of 3000 grab samples were assayed by using the rapid spectral method to determine 32 elements and chemical adsorption to determine gold. Spectral assay data were processed in order to determine the distribution of 24 elements. Background (Cf) values were calculated using Lognormal Statistics software. 

BMDP Statistical Software 1981, W. J. Dixon, ed. University of California Press Berkeley, CA, 1981. 

Acute Oral Toxicity Up-and-Down Procedure (Updated Guideline, adopted 20 December 2001) (Statistical software)... 

Some remarks are in order regarding the use of skewness and knrtosis statistics as reported by statistical software ... 

The univariate response data on all standard biomarker data were analysed, ineluding analysis of variance for unbalaneed design, using Genstat v7.1 statistical software (VSN, 2003). In addition, a-priori pairwise t-tests were performed with the mean reference value, using the pooled variance estimate from the ANOVA. The real value data were not transformed. The average values for the KMBA and WOP biomarkers were not based on different flounder eaptured at the sites, but on replicate measurements of pooled liver tissue. The nominal response data of the immunohistochemical biomarkers (elassification of effects) were analysed by means of a Monte... 

Determination of sodium in a soil extract. Using the five sodium calibration standards already prepared obtain five replicate readings for each sodium standard and calculate the mean emission intensity and RSD for each standard. Aspirate the standards in ascending and descending order of concentration. Aspirate a blank between each standard and zero the instrument. Using a statistical software package construct a... 

F.K. Uno, H.L. Ralston, R.I. Jennrich and P.F. Sampson, Test problems from the pharmacokinetic literature requiring fitting models defined by differential equations, Technical Report No. 61. BMDP Statistical Software, Los Angeles, 1979. 

If a laboratory subscribes to statistical software, it is likely that control charts will be available and the data just need to be entered. When using a regular spreadsheet, there are a couple of tips for drawing the limit lines that might... 

One can use statistical software packages to calculate the level of control the process is under, and one may, for example, use process capability indices that compare the output of an in-control process to the specification limits. Indirect proxies for controllability metrics could also be the amount of materials and/or energy consumed per kg of product caused by excursions outside the control zone. For example, a rejected batch will become waste, and additional mass and energy will be required to replace or rework the rejected batch. 

This model allows us to estimate a response inside the experimental domain defined by the levels of the factors and so we can search for a maximum, a minimum or a zone of interest of the response. There are two main disadvantages of the complete factorial designs. First, when many factors were defined or when each factor has many levels, a large number of experiments is required. Remember the expression number of experiments = replicates x Oevels) " (e.g. with 2 replicates, 3 levels for each factor and 3 factors we would need 2 x 3 = 54 experiments). The second disadvantage is the need to use ANOVA and the least-squares method to analyse the responses, two techniques involving no simple calculi. Of course, this is not a problem if proper statistical software is available, but it may be cumbersome otherwise. 

Experimental data and calculated data for the photodegradation of chlo-rophenols were compared using multivariate analysis and SPSS statistical software. A linear expression was developed using the independent variables Kow and ores and the dependent variable log k/kQ. Calculated values for log k/k0 were obtained from the following linear equation ... 

The hypergeometric distribution can be generalized to a multivariable form, the multivariate hypergeometric distribution, which can be used to extend Fisher s Exact Test to contingency tables larger than 2 by 2 and to multidimensional contingency tables. There is statistical software available to perform these calculations however, due to the complexity of the calculations and the large number of trial tables whose probability of occurrence must be calculated, this extension has received limited use. 

Levels of three individual degradation products and the total amount of degradation impurities were monitored at timepoints of 1, 2, 4, 8, 12, and 24 weeks. Statistical software was used to analyze the data and derive models for the rates of degradation as a function of the temperature and sample water content. The analysis showed that temperature and water content were both significant in their effect on degradation rate (Table 4). The... 

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