Put this table somewhere (I'm using I2 to J8).
<table x:str="" style="border-collapse: collapse; width: 96pt;" border="0" cellpadding="0" cellspacing="0" width="128"><col style="width: 48pt;" span="2" width="64"> <tbody><tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt; width: 48pt;" x:num="0" align="right" height="17" width="64">Time
00:00</td> <td class="xl25" style="width: 48pt;" x:num="" align="right" width="64">Category
0.0</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="2.0833333333333332E-2" align="right" height="17">00:30</td> <td class="xl25" x:num="" align="right">0.5</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="4.1666666666666664E-2" align="right" height="17">01:00</td> <td class="xl25" x:num="" align="right">1.0</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="6.25E-2" align="right" height="17">01:30</td> <td class="xl25" x:num="" align="right">1.5</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="8.3333333333333329E-2" align="right" height="17">02:00</td> <td class="xl25" x:num="" align="right">2.0</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="0.10416666666666667" align="right" height="17">02:30</td> <td class="xl25" x:num="" align="right">2.5</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="0.125" align="right" height="17">03:00</td> <td class="xl25" x:num="" align="right">3.0</td> </tr> </tbody></table>
Then in the 3rd column eg "Column C" use something like =VLOOKUP(A2,$I$2:$J$8,2) and fill it down through the whole column of data.
This will then give a decimal category next to your times.
You then make a sumif formula (in column K) like
=SUMIF($C$2:$C$55,J2,$B$2:$B$55) Where C is your newly parsed decimal category, and B is your count column.
<table x:str="" style="border-collapse: collapse; width: 150pt;" border="0" cellpadding="0" cellspacing="0" width="200"><col style="width: 48pt;" width="64"> <col style="width: 54pt;" width="72"> <col style="width: 48pt;" width="64"> <tbody><tr style="height: 12.75pt;" height="17"> <td class="xl26" style="height: 12.75pt; width: 48pt;" height="17" width="64">Time</td> <td class="xl26" style="width: 54pt;" width="72">Category</td> <td class="xl26" style="width: 48pt;" width="64"> Total</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="0" align="right" height="17">00:00</td> <td class="xl25" x:num="" align="right">0.0</td> <td x:num="" align="right">0</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="2.0833333333333332E-2" align="right" height="17">00:30</td> <td class="xl25" x:num="" align="right">0.5</td> <td x:num="" align="right">0</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="4.1666666666666664E-2" align="right" height="17">01:00</td> <td class="xl25" x:num="" align="right">1.0</td> <td x:num="" align="right">427</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="6.25E-2" align="right" height="17">01:30</td> <td class="xl25" x:num="" align="right">1.5</td> <td x:num="" align="right">340</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="8.3333333333333329E-2" align="right" height="17">02:00</td> <td class="xl25" x:num="" align="right">2.0</td> <td x:num="" align="right">533</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="0.10416666666666667" align="right" height="17">02:30</td> <td class="xl25" x:num="" align="right">2.5</td> <td x:num="" align="right">271</td> </tr> <tr style="height: 12.75pt;" height="17"> <td class="xl24" style="height: 12.75pt;" x:num="0.125" align="right" height="17">03:00</td> <td class="xl25" x:num="" align="right">3.0</td> <td x:num="" align="right">0</td> </tr> </tbody></table>
I hope that makes some sense.