Standard deviation standardization

RSD, relative standard deviation = (standard deviation/mean) x 100. Deviation = [(mean — nominal)/nominal] x 100. 

All uncertainty estimates must be expressed numerically as a standard uncertainty. The term standard uncertainty is analogous to the statistical term standard deviation. A standard uncertainty is therefore an uncertainty estimate expressed as a standard deviation. Standard uncertainties are usually denoted by the symbol u. Uncertainty estimates can be divided into two categories [7] ... 

Relative standard deviation = standard deviation -j- mean... 

Although Euclidean and Mahalanobis distances are the ones most commonly used in analytical chemistry applications, there are other distance measures that might be more appropriate for specific applications. For example, there are standardized Euclidean distances, where each of the dimensions is inversely weighted by the standard deviation of that dimension in the calibration data (standard deviation-standardized), or the range of that dimension in the calibration data (range-standardized). 

Probabilistic sampling, which lies in the core of the DQO process, is based on a random sample location selection strategy. It produces data that can be statistically evaluated in terms of the population mean, variance, standard deviation, standard error, confidence interval, and other statistical parameters. The EPA provides detailed guidance on the DQO process application for the... 

Where appropriate, individual data were presented together with descriptive statistics including mean, standard deviation, standard error of the mean, coefficient of variation (in %), median, minimum, maximum, and the number of relevant observations. 

Standard deviation, standard error, or degree of accuracy can be given in two ways ... 

Sample size Standard deviation Standard error Minimum maximum Standardized ... 

Mean Tonometric Readings (mm Hg) Standard Deviation Standard Error R Regression... 

Applying the first method, four different criteria, namely Dixon s test, Grubbs test, the coefficient of dewness test and the coefficient of kurtosis test are used at a significance level of a = 0.05. If a laboratory mean for each element as single unweighted value was declared to be an outlier by any criterion, it is rejected and the whole procedure repeated until no more outliers could be identified. The remaining laboratory means are then combined in the usual way to provide estimates of the overall mean (consensus value) and its associated standard deviation, standard error and 95% confidence interval. 

There are several concepts and terms that are essential to discussions about QA, even the concept itself. While at a very detailed level any definition can be challenged as being too narrow or too broad, the definitions presented below are useful (20). It should be noted that these terms are quite recent in definition and are not usually given in statistics books. Other terms like pollution have evolved over hundreds of years (21). Some key terms used in the field like reproducibility, standard deviation, standard error, replicate analysis, blanks, spiked samples and blind samples are self-explanatory. 

Uncertainty is expressed as standard deviation or relative standard deviation (%) (= standard deviation x 100/mean)... 

Statistical concepts employed in setting specifications and their relationship to product quality control include accidental and systemic errors, frequency distributions, measures of dispersion, standard deviations, standard errors, and sampling plans. In summary, specifications must be set by taking into account... 

Notes a) % RSD = % Relative standard deviation = standard deviation / mean (triplicate) x 100 b) Fat content (%) as obtained from Agriculture and Agri-Food Canada (corresponds to the accreditation values) c) Labelled value and d) Value obtained by conventional method. 

Mean standard deviation standard error of mean and range. 

Notes FQ fluorescence quenching, ISE ion-selective electrode, CSV cathodic stripping voltammetry SD standard deviation Standard deviation was less than 0.05. 

Using the above equation, the theorehcal sample size needed to represent the bulk composihon of a blend with a given standard deviation can be calculated. Data in the table below are normalized to the relahve standard deviation based on the component concentrahon (P) to allow for easy comparison (relative standard deviation = standard deviation / P x 100). The number of particles is also expressed as grams. It can be seen in the table that the lower the %component in the blend or the greater the confidence in the composihon (lower the acceptable relative standard deviahon), the greater the number of particles are required in the sample. 

Standard deviation Standard deviation of task performance time. 

Sample concentration was 0.5 mg/l Number of repeating oxyethylenes Standard deviation Standard compound Reproduced with permission from T. Okada, Analytical Chemistry, 1990, 62, 734, ACS [32] ... 

As we show in Section al A-1, Appendix 1. the precision of analytical data is the degree of mutual agreement among data that have been obtained in the same way. Precision provides a measure of the random, or indeterminate, error of an analysis. Figures of merit for precision include ahsohiie sumciunl deviation, relative standard deviation, standard error of die mean, coefficient of variation, and variance. These terms are defined in Table l-.ri. 

Repeatability standard deviation (standard deviation of test results obtained under repeatability conditions) Reproducibility standard deviation (standard deviation of test results under reproducibility conditions) ... 

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