Days, Type1, Type2, Name1 and Name2 are arbitrary words
given to named ranges.
Type1 is the name of the third data column in the first array.
To define the name Type1,
select this header and the five data entries below it and
Insert Name Create Top Row
To define the name Type2,
select this header and the three cells to the left of it and
Insert Name Create Right Column

Before you start entering the formula, be sure to select
Tools Options General R1C1 reference style
You can go back to A1 reference style thereafter.