Probability : Example

In this example I show you how to answer it by a Venn diagram or Tree Diagram method.

A group of factory workers were questioned by a popular health magazine and 2/5 were found to take regular exercise. When asked about their eating habits 2/3 replied that they always eat breakfast and, of those who always eat breakfast 9/25 also took regular exercise.


Find the probability that a randomly selected member of the group


(a) always eats breakfast and takes regular exercise,
(b) does not always eat breakfast and does not take regular exercise.
(c) Determine, giving your reason, whether or not always eating breakfast and taking regular exercise are statistically independent.

Venn Diagram Method

Tree Diagram Method


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