Длительность = 'Таблица1'[Дата конца] - 'Таблица1'[Дата начала] 

Мера = 
VAR val =
    MEDIAN ( 'Таблица1'[Длительность] )
VAR d =
    TRUNC ( val )
VAR hhmm =
    FORMAT ( val - d, "hh:mm" )
VAR result = d & " " & hhmm
RETURN
    result

let
  data    = #table ( { "product", "value" }, { { "a", 5 }, { "b", 10 } } ),
  typed   = Table.TransformColumnTypes ( data, { { "value", type number } } ),
  addClmn = Table.AddColumn ( typed, "value_sum", each List.Sum ( typed[value] ), type number )
in
  addClmn

[
  data    = #table ( { "product", "value" }, { { "a", 5 }, { "b", 10 } } ),
  typed   = Table.TransformColumnTypes ( data, { { "value", type number } } ),
  addClmn = Table.AddColumn ( typed, "value_sum", each List.Sum ( typed[value] ), type number )
][addClmn]

let
  data    = #table ( { "product", "value" }, { { "a", 5 }, { "b", 10 } } ),
  typed   = Table.Buffer ( Table.TransformColumnTypes ( data, { { "value", type number } } ) ),
  addClmn = Table.AddColumn ( typed, "value_sum", each List.Sum ( typed[value] ), type number )
in
  addClmn

let
  data    = #table ( { "product", "value" }, { { "a", 5 }, { "b", 10 } } ), 
  typed   = Table.TransformColumnTypes ( data, { { "value", type number } } ), 
  val_sum = List.Sum ( typed[value] ),
  addClmn = Table.AddColumn ( typed, "value_sum", each val_sum, type number )
in
  addClmn

  #"Добавлен пользовательский объект" = Table.AddColumn (
    #"Измененный тип", 
    "Пользовательский", 
    each [ new_date = Date.AddMonths ( [Дата приема], 3 ), result = Date.AddDays ( new_date, Date.Day ( [Дата приема] ) - Date.Day ( new_date ) ) ][
      result
    ], 
    type date
  )

av:=
AVERAGEX (
    VALUES ( 'Таблица1'[Год] );
    VAR PY = 'Таблица1'[Год] - 1
    VAR valueCY =
        CALCULATE ( [кол-во] )
    VAR valuePY =
        CALCULATE ( [кол-во]; 'Таблица1'[Год] = PY )
    VAR result =
        DIVIDE ( valueCY; valuePY )
    RETURN
        result
)

/**
 * Unpivots columns (or optional other columns) while keeping empty fields (with
 * null). Any entry to the 3rd parameter will set to 'Unpivot Other Columns'
 * instead.
 * 
 * @categories table, pivot
 * @author https://github.com/ImkeF
 * @source https://github.com/ImkeF/M
 * @license MIT (c) 2017 Imke Feldmann
 * @version 2021-02-09-1
 */
let
  func = (Table_ as table, Columns as list, optional Others as any) =>
    let
      NonSelectedColumns = List.Difference(Table.ColumnNames(Table_), Columns),
      Unpivot = if Others <> null then NonSelectedColumns else Columns,
      AddColumn = Table.AddColumn(
        Table_,
        "Custom",
        each Record.ToTable(Record.SelectFields(_, Unpivot))
      ),
      Cleanup = Table.RemoveColumns(AddColumn, Unpivot),
      Expand = Table.ExpandTableColumn(Cleanup, "Custom", {"Name", "Value"}, {"Name", "Value"})
    in
      Expand,
  documentation = [
    Documentation.Name = " Table.UnpivotKeepNulls#(cr,lf)",
    Documentation.Description
      = " Unpivots columns (or optional other columns) while keeping empty fields (with null). #(cr,lf)",
    Documentation.LongDescription
      = " Unpivots columns (or optional other columns) while keeping empty fields (with null). Any entry to the 3rd parameter will set to ""Unpivot Other Columns"" instead. #(cr,lf)",
    Documentation.Category = " Table Transformation#(cr,lf)",
    Documentation.Source = " local#(cr,lf)",
    Documentation.Author = " Imke Feldmann: www.TheBIccountant.com .#(cr,lf)",
    Documentation.Examples = {[Description = " #(cr,lf)", Code = " #(cr,lf) ", Result = " #(cr,lf)"]}
  ]
in
  Value.ReplaceType(func, Value.ReplaceMetadata(Value.Type(func), documentation))