Monthy financials expressedas average per day

Hello,

I have a workbook with a worksheet for each day of the month.

A summary sheet shows totals per date (1st, 2nd, 3rd, &tc.).

I want to create a statistical sheet that shows AVERAGES per day of week, for trend analysis.

I have a formula that works to show the totals for each day of the week

=SUMPRODUCT(--(WEEKDAY('FD5'!B10:B40)=1)|'FD5'!S10:S40)

but I want to break that down to an average per day of week.

Please HELP!!!