HL7.TERMINOLOGY\ProbabilityDistributionType

HL7 Terminology (THO)
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CodeSystem: ProbabilityDistributionType

Official URL: http://terminology.hl7.org/CodeSystem/v3-ProbabilityDistributionType		Version: 2.1.0
Active as of 2019-03-20	Responsible: Health Level 7	Computable Name: ProbabilityDistributionType
Other Identifiers: id: urn:oid:2.16.840.1.113883.5.1020

** MISSING DESCRIPTION **

This Code system is referenced in the content logical definition of the following value sets:

Properties

This code system defines the following properties for its concepts

Code

URI

Type

Description

Specializes

Coding

The child code is a more narrow version of the concept represented by the parent code. I.e. Every child concept is also a valid parent concept. Used to allow determination of subsumption. Must be transitive, irreflexive, antisymmetric.

Generalizes

Coding

Inverse of Specializes. Only included as a derived relationship.

internalId

http://terminology.hl7.org/CodeSystem/utg-concept-properties#v3-internal-id

code

The internal identifier for the concept in the HL7 Access database repository.

status

http://hl7.org/fhir/concept-properties#status

code

Designation of a concept's state. Normally is not populated unless the state is retired.

Concepts

This code system http://terminology.hl7.org/CodeSystem/v3-ProbabilityDistributionType defines the following codes:

Code	Display	Definition	internalId	status
B	beta	The beta-distribution is used for data that is bounded on both sides and may or may not be skewed (e.g., occurs when probabilities are estimated.) Two parameters a and b are available to adjust the curve. The mean m and variance s2 relate as follows: m = a/ (a + b) and s2 = ab/((a + b)2 (a + b + 1)).	10756	active
E	exponential	Used for data that describes extinction. The exponential distribution is a special form of g-distribution where a = 1, hence, the relationship to mean m and variance s2 are m = b and s2 = b2.	10752	active
F	F	Used to describe the quotient of two c2 random variables. The F-distribution has two parameters n1 and n2, which are the numbers of degrees of freedom of the numerator and denominator variable respectively. The relationship to mean m and variance s2 are: m = n2 / (n2 - 2) and s2 = (2 n2 (n2 + n1 - 2)) / (n1 (n2 - 2)2 (n2 - 4)).	10755	active
G	(gamma)	The gamma-distribution used for data that is skewed and bounded to the right, i.e. where the maximum of the distribution curve is located near the origin. The g-distribution has a two parameters a and b. The relationship to mean m and variance s2 is m = a b and s2 = a b2.	10751	active
LN	log-normal	The logarithmic normal distribution is used to transform skewed random variable X into a normally distributed random variable U = log X. The log-normal distribution can be specified with the properties mean m and standard deviation s. Note however that mean m and standard deviation s are the parameters of the raw value distribution, not the transformed parameters of the lognormal distribution that are conventionally referred to by the same letters. Those log-normal parameters mlog and slog relate to the mean m and standard deviation s of the data value through slog2 = log (s2/m2 + 1) and mlog = log m - slog2/2.	10750	active
N	normal (Gaussian)	This is the well-known bell-shaped normal distribution. Because of the central limit theorem, the normal distribution is the distribution of choice for an unbounded random variable that is an outcome of a combination of many stochastic processes. Even for values bounded on a single side (i.e. greater than 0) the normal distribution may be accurate enough if the mean is "far away" from the bound of the scale measured in terms of standard deviations.	10749	active
T	T	Used to describe the quotient of a normal random variable and the square root of a c2 random variable. The t-distribution has one parameter n, the number of degrees of freedom. The relationship to mean m and variance s2 are: m = 0 and s2 = n / (n - 2)	10754	active
U	uniform	The uniform distribution assigns a constant probability over the entire interval of possible outcomes, while all outcomes outside this interval are assumed to have zero probability. The width of this interval is 2s sqrt(3). Thus, the uniform distribution assigns the probability densities f(x) = sqrt(2 s sqrt(3)) to values m - s sqrt(3) >= x <= m + s sqrt(3) and f(x) = 0 otherwise.	10748	active
X2	chi square	Used to describe the sum of squares of random variables which occurs when a variance is estimated (rather than presumed) from the sample. The only parameter of the c2-distribution is n, so called the number of degrees of freedom (which is the number of independent parts in the sum). The c2-distribution is a special type of g-distribution with parameter a = n /2 and b = 2. Hence, m = n and s2 = 2 n.	10753	active