duration without hours?

[Matt Price <moptop99@gmail.com>]

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I have a silly table I am planning to use to teach myself a little bit
about R; it contains durations measured in minutes and seconds:

* Kayaking Log
| 500m Trial | <2016-09-14 Wed> | <2016-09-15 Thu> |     Mean |
|------------+------------------+------------------+----------|
|          1 |         00:02:48 |         00:02:34 | 00:02:48 |
|          2 |         00:02:38 |         00:02:47 |          |
|          3 |         00:02:42 |         00:02:42 |          |
|          4 |         00:02:36 |         00:02:40 |          |
|          5 |         00:02:58 |         00:02:37 |          |
|------------+------------------+------------------+----------|
|       MEAN |         00:02:44 |         00:02:40 |          |

#+TBLFM: $2=vmean(@2..@-1);T::$3=vmean(@2..@-1);T::$4=vmean($2..$-1);T

I have a bunch of questions but will start with what is maybe the most
basic: can I write durations in minutes and seconds only? the extra 00: is
sort of annoying to type when I am tired.

Later I'll want to think about the best way to turn this data into a plot
of fastest, slowest, and mean times day-to-day. But not tonight, I'm beat!
Thanks,
Matt

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