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In probability theory and statistics, the coefficient of variation (CV) is a measure of dispersion of a probability distribution. It is defined as the ratio of the standard deviation  to the mean  : Probability theory is the mathematical study of phenomena characterized by randomness or uncertainty. ...
Template:Otherusescccc A graph of a bell curve in a normal distribution showing statistics used in educational assessment, comparing various grading methods. ...
In descriptive statistics, statistical dispersion (also called statistical variability) is quantifiable variation of measurements of differing members of a population within the scale on which they are measured. ...
In mathematics and statistics, a probability distribution, more properly called a probability density, assigns to every interval of the real numbers a probability, so that the probability axioms are satisfied. ...
In probability and statistics, the standard deviation of a probability distribution, random variable, or population or multiset of values is defined as the square root of the variance. ...
In statistics, mean has two related meanings: Look up mean in Wiktionary, the free dictionary. ...
 The coefficient of variation is a dimensionless number that allows comparison of the variation of populations that have significantly different mean values. It is often reported as a percentage (%) by multiplying the above calculation by 100. In dimensional analysis, a dimensionless number (or more precisely, a number with the dimensions of 1) is a pure number without any physical units. ...
The coefficient of variation is often used when discussing the normal distribution for positive mean values with the standard deviation significantly less than the mean. This application may be reasonable for many models, but breaks down theoretically unless the distribution is known to be positive valued, since there is a nonzero probability that the distribution will assume a negative value. The normal distribution, also called Gaussian distribution (named after Carl Friedrich Gauss, a German mathematician, although Gauss was not the first to work with it), is a probability distribution of great importance in many fields. ...
When the mean value is near zero, the coefficient of variation is sensitive to change in the standard deviation, limiting its usefulness.
The coefficient of variation is also common in applied probability fields such as renewal theory, queueing theory, and reliability theory. In these fields, the exponential distribution is often more important than the normal distribution. The standard deviation of an exponential distribution is equal to its mean, so its coefficient of variation is equal to 1. Distributions with CV < 1 (such as an Erlang distribution) are considered low-variance, while those with CV > 1 (such as a hyper-exponential distribution) are considered high-variance. Some formulas in these fields are expressed using the Squared coefficient of variation, often abbreviated SCV. Renewal theory is a branch of probability theory with an interesting and varied range of applications. ...
Queueing theory (also commonly spelled queuing theory) is the mathematical study of waiting lines (or queues). ...
Reliability theory developed apart from the mainstream of probability and statistics, and was used originally as a tool to help nineteenth century maritime insurance and life insurance companies compute profitable rates to charge their customers. ...
In probability theory and statistics, the exponential distributions are a class of continuous probability distribution. ...
The normal distribution, also called Gaussian distribution (named after Carl Friedrich Gauss, a German mathematician, although Gauss was not the first to work with it), is a probability distribution of great importance in many fields. ...
In probability theory and statistics, the exponential distributions are a class of continuous probability distribution. ...
The Erlang distribution is a continuous probability distribution with wide applicability primarily due to its relation to the exponential and Gamma distributions. ...
In probability theory, a hyper-exponential distribution is a continuous distribution such that the probability density function of the random variable X is given by: Where is an exponentially distributed random variable with rate parameter , and is the probability that X will take on the form of the exponential distribution...
The absolute value of the coefficient of variation expressed as a percentage is often referred to as the relative standard deviation (RSD or %RSD). In mathematics, the absolute value (or modulus1) of a real number is its numerical value without regard to its sign. ...
In probability theory and statistics, the Relative Standard Deviation (RSD or %RSD) refers to the absolute value of the coefficient of variation expressed as a percentage. ...
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