The ?CodeList? class 'StatisticalFunctionCode' specifies the type of statistical function that is applied to the base observable property to define the statistical summary; e.g. maximum air temperature.<br /></p><p><br /></p><p>Note that WMO provides two code-tables listing statistical operators: <br /></p><p>- WMO No. 306 Vol I.2 Part B FM 92 GRIB code-table 4.10 'Type of statistical processing'; and<br /></p><p>- WMO No. 306 Vol I.2 Part B FM 94 BUFR code-table 0 08 023 'First-order statistics'<br /></p><p><br /></p><p>The GRIB2 code-table is defined as the 'recommended' vocabulary for this ?CodeList? class but lacks some of the necessary terms. For example, the GRIB code-table includes 'Average' but does not include 'Mean', 'Mode' or 'Median' (which can be found in the BUFR code-table). However, the BUFR code-table is _NOT_ chosen because 'Accumulation' is entirely missing. Given that 'extensibility' is set to 'any', authors are free to refer to their preferred 'statistical operator' vocabulary. The GRIB code-table is only a recommendation. <br /></p>