4.2.12.395 Code System http://hl7.org/fhir/observation-statistics

Code Display Definition

average Average The [mean](https://en.wikipedia.org/wiki/Arithmetic_mean) of N measurements over the stated period

maximum Maximum The [maximum](https://en.wikipedia.org/wiki/Maximal_element) value of N measurements over the stated period

minimum Minimum The [minimum](https://en.wikipedia.org/wiki/Minimal_element) value of N measurements over the stated period

count Count The [number] of valid measurements over the stated period that contributed to the other statistical outputs

totalcount Total Count The total [number] of valid measurements over the stated period, including observations that were ignored because they did not contain valid result values

median Median The [median](https://en.wikipedia.org/wiki/Median) of N measurements over the stated period

std-dev Standard Deviation The [standard deviation](https://en.wikipedia.org/wiki/Standard_deviation) of N measurements over the stated period

sum Sum The [sum](https://en.wikipedia.org/wiki/Summation) of N measurements over the stated period

variance Variance The [variance](https://en.wikipedia.org/wiki/Variance) of N measurements over the stated period

20-percent 20th Percentile The 20th [Percentile](https://en.wikipedia.org/wiki/Percentile) of N measurements over the stated period

80-percent 80th Percentile The 80th [Percentile](https://en.wikipedia.org/wiki/Percentile) of N measurements over the stated period

4-lower Lower Quartile The lower [Quartile](https://en.wikipedia.org/wiki/Quartile) Boundary of N measurements over the stated period

4-upper Upper Quartile The upper [Quartile](https://en.wikipedia.org/wiki/Quartile) Boundary of N measurements over the stated period

4-dev Quartile Deviation The difference between the upper and lower [Quartiles](https://en.wikipedia.org/wiki/Quartile) is called the Interquartile range. (IQR = Q3-Q1) Quartile deviation or Semi-interquartile range is one-half the difference between the first and the third quartiles.

5-1 1st Quintile The lowest of four values that divide the N measurements into a frequency distribution of five classes with each containing one fifth of the total population

5-2 2nd Quintile The second of four values that divide the N measurements into a frequency distribution of five classes with each containing one fifth of the total population

5-3 3rd Quintile The third of four values that divide the N measurements into a frequency distribution of five classes with each containing one fifth of the total population

5-4 4th Quintile The fourth of four values that divide the N measurements into a frequency distribution of five classes with each containing one fifth of the total population

skew Skew Skewness is a measure of the asymmetry of the probability distribution of a real-valued random variable about its mean. The skewness value can be positive or negative, or even undefined. Source: [Wikipedia](https://en.wikipedia.org/wiki/Skewness)

kurtosis Kurtosis Kurtosis is a measure of the "tailedness" of the probability distribution of a real-valued random variable. Source: [Wikipedia](https://en.wikipedia.org/wiki/Kurtosis)

regression Regression Linear regression is an approach for modeling two-dimensional sample points with one independent variable and one dependent variable (conventionally, the x and y coordinates in a Cartesian coordinate system) and finds a linear function (a non-vertical straight line) that, as accurately as possible, predicts the dependent variable values as a function of the independent variables. Source: [Wikipedia](https://en.wikipedia.org/wiki/Simple_linear_regression) This Statistic code will return both a gradient and an intercept value.