====== Statistics control Quantile method ======


==== Description of Method ==== 

The distribution of all observations within one month timespan is represented by the [[http://en.wikipedia.org/wiki/Quartile|quartiles]] Q1, Q2 and Q3.
The station and month specific reference quartiles Q1', Q2' and Q3' is calculated from the climate database either by the previous ten years or from a regional reference station.

A neighbour station n is selected with a corresponding set of quartiles Q1n, Q2n and Q3n.
The neighbour station also have the station and month specific reference quartiles Q1'n, Q2'n and Q3'n.

An error is detected when

<nowiki>|Q1 - Q1'| - |Q1n - Q1n'| > tol1  and  |Q1 - Q1'| > tol2 </nowiki>

or

<nowiki>|Q2 - Q2'| - |Q2n - Q2n'| > tol3  and  |Q2 - Q2'| > tol4 </nowiki>

or

<nowiki>|Q3 - Q3'| - |Q3n - Q3n'| > tol5  and  |Q3 - Q3'|  > tol6 </nowiki>

where

tol1 - tol6 are six tolerance values.

==== Quality Control Level ====

  * QC2d-4


==== Run Parameters ====

It shall be possible to run the algorithm for

  * UU
  * NN
  * HL
  * VV
  * QO


==== Characteristics of the data to which the method is applied ====

__CONTROLINFO AND/OR USEINFO__

  * none
 
__TYPEID, OTHER METADATA__

  * all typeid

==== Flag Settings ====

__SPECIFICATION OF CONTROLFLAGS TO BE SET FOR EXPECTED RESULTS OF THE ALGORITHM, I.E. CONSIDER BOTH POSITIVE AND NEGATIVE RESULTS__

  * fstat=1 on no error detection
  * fstat=2 on error detection


__EXPECTIONS OF THE USEINFO FLAGS CORRESPONDING TO CONTROLINFO FLAG SETTINGS__

  * fstat=2  -> useinfo(2)=2



==== Dependencies ====

  * Definition of neighbour station
  * Definition of regions and related region reference station
  * Extracts from KDVH