week average on missing values

bazari , you might want to achieve your goal in Power Query,

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("bc9BDoUgDIThq7ywNpEORfAsxvtfQ9BMzcS3oJuPJv2PI1lezVZk5LSkNp5jjF86l8dAM5pZYCGC2D3QiYU4BrESnbjXwI1Y/2w24vY9tktIEdslZJp1IrKETESEwCTk3myBkJD7x4tFQib2CIFLiByLKiH+2HkB", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [date = _t, Weekday = _t, #"week num" = _t, #"Values (KPMR)" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"date", type date}, {"Weekday", Int64.Type}, {"week num", Int64.Type}, {"Values (KPMR)", Int64.Type}}),
    #"Grouped Rows" = Table.RemoveColumns(Table.Group(#"Changed Type", {"week num"}, {{"ar", each _, type table [date=nullable date, Weekday=nullable number, week num=nullable number, #"Values (KPMR)"=nullable number]}}), {"week num"}),
    Population = Table.TransformColumns(
        #"Grouped Rows", 
        {"ar", 
        each let kpmr = [#"Values (KPMR)"], avg = List.Sum(kpmr)/List.NonNullCount(kpmr) in Table.ReplaceValue(
            _, null, avg, Replacer.ReplaceValue, {"Values (KPMR)"}
        )}
    ),
    #"Expanded ar" = Table.ExpandTableColumn(Population, "ar", {"date", "Weekday", "week num", "Values (KPMR)"}, {"date", "Weekday", "week num", "Values (KPMR)"})
in
    #"Expanded ar"