Probability and Statistics

 Visualizing odds

 From: Daithi Address: (none) Date: 22 March 2011 Subject: Tavli question Forum: 2+2 Backgammon Forum

```Here's a simple tip I thought I'd share. This tip is REALLY basic, but it
helped me visualize odds.

When I progressed beyond the bare basics of backgammon I learned that it
was useful to know the odds of getting hit, or hitting someone, or coming
in off the bar, or similar situations. I learned how to count up these
odds, and knew that there was an 11/36 chance of rolling one specific
number, and a 20/36 chance of rolling one of two specific numbers, etc. The
problem was that although I had a general idea of what something like 11/36
or 20/36 meant, it was still a little fuzzy in my mind's eye. However, I
found a way to visualize these fractions so that they became crystal clear.

I divide the fraction by 3 and then visualize the result as time on a
clock. So 27/36 would become 9/12 and thus 9 o'clock (in practice I just
divide the top number by 3). When you can't divide the numerator evenly you
will be left with either 1 or 2 left over and these would correspond to 20
minutes or 40 minutes respectively. For example, 19/36 would be 6:20 (i.e.
20 past 6), and 11/36 would be 3:40 (but visualize on a clock with hands).
Now my mind's eye has a very clear reference for the odds of a roll.

I don't know if that helps anybody else, but it helped me. I also haven't
seen this tip in print anywhere, so I thought I'd throw it out there.
```

### Probability and Statistics

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How often is too often?  (Gary Wong, Oct 1998)
Losing after bearing off 14 checkers  (Daniel Murphy, July 1999)
Number of games per match  (Jason Lee+, Jan 2005)
Number of rolls to enter x checkers from bar  (Michael Depreli+, Mar 2011)
Visualizing odds  (Daithi, Mar 2011)