Array of True values - Time averages

[Sayth]

If I create a basic table like this using a circular reference as a timestamp

Time	Call Qual
27/08/2015 12:07	2
27/08/2015 12:07	3
27/08/2015 12:30	3
27/08/2015 12:37	4
27/08/2015 12:39	3
27/08/2015 12:41	3
27/08/2015 12:45	4
27/08/2015 12:47	3
27/08/2015 12:50	4
27/08/2015 12:55	4
28/08/2015 9:21	3
28/08/2015 9:28	4
28/08/2015 9:43	3
28/08/2015 9:48	2
28/08/2015 10:07	3
28/08/2015 10:10	3
28/08/2015 10:18	3

How can I create an average of blocks of time of 15minutes. I am thinking I need to take my current formula which identifies the blocks but should there be an array in the True value to select all numbers?

This is my current formula

=IF(Sheet2!C2/1440 < (Sheet2!D:D/1440) > (Sheet2!C2/1440 + 15 ), "Yes", "No")

Note When sheet saved "yes" becomes #value I think because of circular reference in timestamp

Day	First Time	15	30	45
27/08/2015	27/08/2015 12:07	Yes		
28/08/2015

 

[DRSteele]

I suggest that the error #value occurs because you've got any array inside the IF function (i.e., the D:D). Try invoking the formula with CTR SHIFT ENTER instead of just ENTER in order to make Excel deal with that function-argument array operation.

 

[Sayth]

I suggest that the error #value occurs because you've got any array inside the IF function (i.e., the D:D). Try invoking the formula with CTR SHIFT ENTER instead of just ENTER in order to make Excel deal with that function-argument array operation.

Thanks