This code system http://hl7.org/fhir/observation-statistics defines the following codes:
|
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. |