Pivot Table Excel 07 - change value field/formula for group of rows

[martincsr]

Hello - I am working with a set of survey data (503 responses to 237 questions) and creating cross-tabs in excel. Rather than using "sum" to look at the totals, I actually want the average of the data and in some cases, the count. It is incredibly time consuming to change each row inidividually, is there a way to change a group at once - or potentially change the default?

Thank you!!