Frequency and sumif

[tessda]

Hi Guys, hope someone can help. I have data consisting of, say in Col A times (in minutes) and in Col B No of passengers. I have created a frequency table with the bin consisting of 15 minute "timeslots". It is easy to compile this frequency table. I however need to find a formula that will calculate the number of passengers per "timeslot", which I am struggling to compile. Can someone please help?

[daddylonglegs]

So lets say your time slots start at 06:00. List these in D2 down, e.g. 06:00 in D2, 06:15 in D3, 06:30 in D4 etc

Now in E2 you can use this formula for the number of passengers between in the 06:00-06:15 timeslot

=SUMPRODUCT(--(A$2:A$1000>=D2),--(A$2:A$1000<D3),B$2:B$1000)

copy formula down

[tessda]

Thanx daddylonglegs for that quick response. I had to tweak it a bit and obtained the results I wanted!!