Fruit for thought on tooth decay.

This article and Smokers alerted to dental dangers point to the issue of the many factors which may affect a particular outcome, in this case problems with teeth. The claim for fruit is

Pr (tooth decay | eat "lots of fruit regularly") = 2 Pr (tooth decay | eat "not as much fruit").

[Here Pr (A | B) is the probability of event A occurring given the occurrence of event B.]

One could also interpret the quote in the second paragraph study as implying a regression study which might be represented by a scattergram. On one axis a measure of fruit consumption would be represented while on the other a measure of tooth decay would be given. Students might like to draw what a scattergram representing the suggested relationship would look like:

Questions concerning the definition of terms are definitely in order. Also in a real-world setting one would have to consider the other relative benefits of eating fruit.

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