{"resourceType":"CodeSystem","id":"observation-statistics","meta":{"lastUpdated":"2021-01-17T07:06:13.533+11:00"},"url":"http://terminology.hl7.org/CodeSystem/observation-statistics","identifier":[{"system":"urn:ietf:rfc:3986","value":"urn:oid:2.16.840.1.113883.4.642.4.1126"}],"version":"4.0.1","name":"StatisticsCode","title":"StatisticsCode","status":"draft","experimental":false,"date":"2021-01-17T07:06:13+11:00","publisher":"HL7 (FHIR Project)","contact":[{"telecom":[{"system":"url","value":"http://hl7.org/fhir"},{"system":"email","value":"fhir@lists.hl7.org"}]}],"description":"The statistical operation parameter -\"statistic\" codes.","caseSensitive":true,"valueSet":"http://hl7.org/fhir/ValueSet/observation-statistics","content":"complete","concept":[{"code":"average","display":"Average","definition":"The [mean](https://en.wikipedia.org/wiki/Arithmetic_mean) of N measurements over the stated period."},{"code":"maximum","display":"Maximum","definition":"The [maximum](https://en.wikipedia.org/wiki/Maximal_element) value of N measurements over the stated period."},{"code":"minimum","display":"Minimum","definition":"The [minimum](https://en.wikipedia.org/wiki/Minimal_element) value of N measurements over the stated period."},{"code":"count","display":"Count","definition":"The [number] of valid measurements over the stated period that contributed to the other statistical outputs."},{"code":"total-count","display":"Total Count","definition":"The total [number] of valid measurements over the stated period, including observations that were ignored because they did not contain valid result values."},{"code":"median","display":"Median","definition":"The [median](https://en.wikipedia.org/wiki/Median) of N measurements over the stated period."},{"code":"std-dev","display":"Standard Deviation","definition":"The [standard deviation](https://en.wikipedia.org/wiki/Standard_deviation) of N measurements over the stated period."},{"code":"sum","display":"Sum","definition":"The [sum](https://en.wikipedia.org/wiki/Summation) of N measurements over the stated period."},{"code":"variance","display":"Variance","definition":"The [variance](https://en.wikipedia.org/wiki/Variance) of N measurements over the stated period."},{"code":"20-percent","display":"20th Percentile","definition":"The 20th [Percentile](https://en.wikipedia.org/wiki/Percentile) of N measurements over the stated period."},{"code":"80-percent","display":"80th Percentile","definition":"The 80th [Percentile](https://en.wikipedia.org/wiki/Percentile) of N measurements over the stated period."},{"code":"4-lower","display":"Lower Quartile","definition":"The lower [Quartile](https://en.wikipedia.org/wiki/Quartile) Boundary of N measurements over the stated period."},{"code":"4-upper","display":"Upper Quartile","definition":"The upper [Quartile](https://en.wikipedia.org/wiki/Quartile) Boundary of N measurements over the stated period."},{"code":"4-dev","display":"Quartile Deviation","definition":"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."},{"code":"5-1","display":"1st Quintile","definition":"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."},{"code":"5-2","display":"2nd Quintile","definition":"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."},{"code":"5-3","display":"3rd Quintile","definition":"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."},{"code":"5-4","display":"4th Quintile","definition":"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."},{"code":"skew","display":"Skew","definition":"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)."},{"code":"kurtosis","display":"Kurtosis","definition":"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)."},{"code":"regression","display":"Regression","definition":"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."}]}