Description measurement

It is important to know the effectiveness of the model for predicting values however, it is also important to know the strength of the linear relationship between the two variables (known and predicted) being studied. This is achieved using the linear correlation coefficient (Pearson s product moment correlation coefficient), r, as a descriptive measure for the strength of the linear relationship (straight line) between the two variables ... 

The critical analysis of the numerical results placed in Tables 5-8 instructs that for a given adsorption system, one can obtain a comparably accurate descriptions (measured by the q values) of the experimental isotherms on the basis of different theoretical relationships. Since different adsorption equations relate to different paires of Bq and A values, thus it must be emphazised that the adsorbent structural heterogeneity description based on the method presented above has a conventional character and is, similarly as an adsorbent specific surface area, connected with the applied theoretical model. 

Another descriptive measure of variability or dispersion is the percentile. The Pth percentile is the value of the random variable, X = X p, such that ... 

Theoretical descriptions measure the degree of Rydberg and/or intravalency shell character in the upper electronic state by... 

Commonly used descriptive statistics include measures that describe where the middle of the data is. These measures are sometimes called measures of central tendency and include the mean, median, and mode. Another category of measures describes how spread out the data is. These measures are sometimes called measures of variability and include the range, variance, and standard deviation. Additional descriptive measures can include percentages, percentiles, and frequencies. In safety performance measurement, the safety professional must determine the format of the data (i.e., ratio, interval, ordinal, or categorical) that will be collected and match the data format to the appropriate statistic. As will be discussed in the following sections, certain descriptive statistics are appropriate for certain data formats. 

Descriptive Statistics statistical techniques that are used to describe the population or sample. Commonly used descriptive statistics include measures of central tendency mean, median and mode and measures of variability range, variance and standard deviation. Additional descriptive measures can include percentages, percentiles and frequencies. 

Perhaps the simplest descriptive measure used in research is some sort of average. The term some sort of average is used because more... 

Notably, rj) depends on the carbon load Lc, which changes during burn-off with time and, in the case of a resistance of pore diffusion, also with the radial position in the particle. The Thide approach as given by Eqs. (6.9.5) and (6.9.6) is then no longer exactly valid, and numerical simulations are needed. Nevertheless, the initial effectiveness factor ijpore.o may be used as a descriptive measure for the pore diffusion resistance although [Pg.640]

Description Measurement precision is usually expressed numerically by measures of imprecision, such as standard deviation. The precision of a set of results, which have been performed under stated experimental conditions, can be quantified as standard deviation [27]. Precision is normally differentiated as repeatability and reproducibility. 

Description Measurement precision is usually expressed numerically by measures of imprecision, such as standard deviation, variance, or coefficient of variation, under the specified conditions of measurement. When a measurement precision is given, it is important to specify the conditions. These conditions can be, for example, repeatability condition of measurement, intermediate precision condition of measurement, or reproducibility condition of measurement (see ISO 5725-3 1994 and see below). The measurement precision is used to define measurement repeatability, intermediate measurement precision, and measurement reproducibiUty. In the VIM, it is mentioned that sometimes measurement precision is erroneously used to indicate measurement accuracy. 

Description Measurement results for the distances between the Earth and the Moon and between Paris and London are, for example, metrologically comparable when they are both metrologically traceable to the same measurement unit, for example, the meter. 

Kurtosis n A primary measure of shape or descriptive measure which describes the peakedness of a probability distribution, population or sample. It is ideally the 4 normalized central moment (or by many authors as the 4 normalized central moment minus 3, which is also called the excess kurtosis or simply the excess) and is often denoted as k or 72- The precise mathematical definition of kurtosis for a random variable, X, defined on a probability space, S, is given by ... 

Mathematical Expectation See Expectation Value. Mean n The primary descriptive measure of a probability... 

Skewness n The most often used descriptive measure of the deviation from symmetry of a probability distribution, population or sample. It is the 3 normalized central moment and is often denoted as y or yi. The precise mathematical definition of skewness for... 

Standard Deviation n A measure of the spread or dispersion of a random variable, probability distribution, population, or sample from the mean. It is defined as the positive square root of the variance and is one of the most used descriptive measures of a random variable, probability distribution, population or sample. The variance of a random variable is defined as the second central moment of the random variable and is often denoted by cr where cr is the standard deviation. The precise mathematical definition of the standard... 

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