# Average Number of Arms

### What is the **probability** that the next person you meet has an **above average** number of arms?

#### Is it:

Impossible Unlikely Likely Very Likely Certain |

## Solution

Let's imagine a small town of 2,000 people.

Now let's say one of them only has one arm.

**So the total number of arms is 3,999.**

The average number of arms per person is:

number of arms | = | 3,999 | = | 1.9995 |

number of people | 2,000 |

So **2** is above average!

We can now see that 1,999 of the people in our small town has an above average number of arms. They have 2 arms and the average is 1.9995.

If we meet one person at random from our small town, 1,999 out of 2,000 will have an above average number of arms.

The probability of meeting one of these people is 1,999 out of 2,000. This can be expressed as:

1,999 | = | 0.9995 |

2,000 |

If the probability was **1.0** it would be certain that the next person
we meet would have an above average number of arms. It is not **1.0** but it is close. So we can say that it is:

Not quite what you expected, hey?