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### What is a Biased Die?

```
Date: 03/01/2002 at 15:06:04
From: Rehan Basim
Subject: Probability

What is a biased die, and how do we find the probability when the dice
are biased? Would you please give an example? I would be grateful to
you.
```

```
Date: 03/03/2002 at 23:56:32
From: Doctor Twe
Subject: Re: Probability

Hi Rehan - thanks for writing to Dr. Math.

A biased die is the opposite of a fair die. On a fair die, every
number has an equal chance of being rolled (1/6 on a cubic 6-sided
die). On a biased die, some numbers are more likely to be rolled than
others. This may be due to the die's shape - shaving some edges, for
example, or having weights inside the die, or other means of "fixing"
it.

For example, a biased die might have the following probabilities:

No.   Prob
---   ----
1    1/12 =  1/12
2    1/12 =  1/12
3    1/12 =  1/12
4    1/6  =  2/12
5    1/4  =  3/12
6    1/3  =  4/12
-----
12/12

Notice that the sum of all the probabilities must still equal 1.

I hope this helps. If you have any more questions, write back.

- Doctor TWE, The Math Forum
http://mathforum.com/dr.math/
```
Associated Topics:
High School Probability

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