Using index and match to find average

Hi I'm wondering if someone cud help me. I am trying to use index and match to find the average of a number of columns of cells and output the answer in another table. Been at it for ages but can't seem to get it to work. Any help wud be greatly appreciated. Thanks

This is the latest formula ive been tryin to sort out
=AVERAGE(INDEX(B2:G9,),MATCH(I8,B1:G1,0),INDEX(C2:C9,),MATCH(I8,B1:G1,0)INDEX(D2:D9,),MATCH(I8,B1:G1,0)INDEX(E2:E9,),MATCH(I8,B1:G1,0),INDEX(F2:F9,),