Friday, December 4, 2009

Ana's Questions (Below) Answered

We found a linguist to answer Ana's first question and a professor of mathematics to answer the second. Here's what they had to say. First, the linguist:

1. "Bring" and especially "take" have hundreds of meanings, but as used in the case Ms. Mendez mentions, they mean the same thing.

Well, that was simple! Now, for the math:

2. Both situations are figured correctly: if there are 23 people selected at random in a group, the odds are even that two will share the same birthday. The explanation is rather complicated, and the Wikipedia article you cited does a decent job of it.

In the second situation, adding a 24th person to a group with no matches, the odds are indeed about 14 to 1 that there will not be a match.

There is no problem with Ms. Mendez's logic. The difficulty is in realizing that we are talking about two different problems! In the first group, the people are gathered at random--we do not know what their birthdates are. In the second group, we do know--there are NO matches. That is a different problem! That changes everything!

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