=AverageIf(SheetA!$A:$A;A;SheetA!B:G)

A       B   C   D   E   F   G
Text1   1   2   3   1   2   3
Text2   2   3   1   1   1   1
Text3   1   1   2   1   2   2
Text4   3   5   2   4   5   1
Text5   4   2   2   2   2   2

A       B
Text1   2
Text5   2.33

A       B
Text1   1
Text5   4