Is there anyway I can take the average of the numbers in a column but only
including the numbers where the cells in the next door column in the same row
contain a certan word

e.g.

A B
1 Valid 10
2 Invalid 1
3 Invalid 5
4 Valid 5
5 Valid 3

How to I get the average of the numbers in column B but only if the adjacent
cell in column A = Valid. Answer here would be 6

Thanks

John