Google Sheet SUMIF across range of cells

Question

I am trying to use a formula in google sheets to find averages based on the contents of a different cell.

Below is some sample data, I am pretty sure I have done similar in the past in Excel by using table headers as a reference but struggling to see how to achieve this in google sheets. Columns B, C, D to be calculated, currently this is the formula used for D3 (same sort of thing for D4) =IFERROR(ROUND(SUM(E3:H3)/COUNT(E3:H3),2),0)

Just needing to work out the formula for the cells with red text, any help would be appreciated.

as an example C3 would be the average for any numbers in row 3 where it has DeviceB e.g. (2+10+6)/3

Answer 1

Try

=AVERAGEIF($E$2:$H$2,B$1,$E3:$H3)

AVERAGEIF