The columns i made on the first page: A,B, and C (the formatting here doesnt show it well though...)
name
vs RHP
vs LHP
albert pujols
0.287
0.321
then on the next page called sheet 2 I made this:
name
pitcher type
avg vs
albert pujols
RHP
0.287
and in cell C2 I wrote the formula: =IF(B2="RHP",Sheet1!B2,Sheet1!C2)
you have to be careful about what the sheet name is or the formula will be wrong, since the formula is referencing another sheet, it has to be named correctly. Also be sure to type either "RHP" or "LHP" in correctly,(actually RHP needs to be correct since I wrote the formula to mean that anything other than "RHP" in that cell will come up with what the avg is vs LHP. Hope this helps!