Average Cell Range based on Day of Week

[kyddrivers]

I am trying to average the values of a range of cells based on the day of the week.

The spreadsheet is setup as follows:

Column A:	Column B:
1/4/15	23.90%
1/5/15	14.39%
1/6/15	4.62%
1/7/15	5.71%
1/8/15	18.32%
1/9/15	31.62%
1/10/15	11.28%
1/11/15	13.13%
1/12/15	29.40%
1/13/15	8.57%
1/14/15	14.44%
1/15/15	33.21%
1/16/15	3.33%
1/17/15	14.81%

<tbody>
</tbody>

What I am attempting to do is Average the cells in column b if the date in column a is a Sunday.

I have tried using a simple If(weekday(A1:A14)=1, Average(B1:B14), "") and this returns a #value error, but I don't think it would give me the answer of 18.52% I am looking for.

I have tried AverageIf(B1:B14, Weekday(A1:A14)=1) and I get #div/0!

Any help is greatly appreciated.

Thanks in advance!!

 

[svendiamond]

This might be an overly complicated formula but it works:

=SUMPRODUCT(--(WEEKDAY(A2:A15)=1),B2:B15)/SUMPRODUCT(--(WEEKDAY(A2:A15)=1))

 

[Aladin Akyurek]

Control+shift+enter, not just enter:

=IFERROR(AVERAGE(IF(WEEKDAY($A$2:$A$15,2)=7,$B$2:$B$15)),"")

where 7 = Sunday.

 

[kyddrivers]

Thank you for the quick and excellent solutions!!