Selecting data from a table

[kalgatha]

Hey guys. I'm working with a rather large table and I'm trying to take an average of values in a certain range under a constraint. So lets say i have a list of 7000 rows and 3 columns. I want the average of all the values in column 3 where the values in column 1 are greater than 90, and where the values in column 2 fall within a set range(for instance 70-80). the only way i know to do it is:

=AVERAGE(IF(A1:A7000>90,IF(IF(80>=B1:B7000,B1:B7000, FALSE)>=70,C1:C7000,FALSE), FALSE))

but when I do this it will only give me the average of everything that meets the B>70 and A>90 constraint. it doesn't see the <80...so what can I do to make this function only select values within the range and not on either side of it? thanks!

 

[Desu Nota from Columbus]

=sumproduct((a1:a7000>90)*(b1:b7000>=70)*(b1:b7000<=80),c1:c7000)/sumproduct((a1:a7000>90)*(b1:b7000>=70)*(b1:b7000<=80))