Suppose an insurance company sells a policy to families with children. In order to avoid keeping track of how many children are in each family, the policy covers all the children in the family (so the policy is a better deal for families with lots of children).

  Getting Started

If the U.S. Census data says that "The average family size in the US is 3.14.", what is the average size of families covered by the policy?

  Going Deeper

What is the average number of children per family in your school? You could ask the people in your class, but that is not everyone in your school, so how confident are you of your answer?

Communicated by A. Heinricher.