I stuck on a graphing problem. Can anyone help.

I have a list of the times of day when I make phone calls. For example

13:31
14:02
14:21
15:04
15:12
15:19
15:23
15:47
16:04
16:44

I want them in a graph to see at what time of day I usually make calls.

FIRST, can Excel group that data into 30 minute intervals and then give a
count of the number of entries?

For example, betweem 15:00 and 15:30 there were 4 calls.

SECOND, could Excel show a chart of the data? Perhaps a bar chart or some
circle chart.