Chapter 7.3, Problem 7.63E

To determine

To find: the probability that the student uses MySpace regularly.

Answer to Problem 7.63E

  $P\left(B|A\right)=0.4941$

Explanation of Solution

Given:

Suppose

A= profile on Facebook

B=uses MySpace regularly

  $\begin{array}{l}P\left(A\right)=0.85\\ P\left(B\right)=0.54P\\ P\left(A\cap B\right)=0.42\end{array}$

Formula used:

Conditional Probability

  $P\left(B|A\right)=\frac{P\left(A\cap B\right)}{P\left(A\right)}$

Calculation:

  $\begin{array}{c}P\left(B|A\right)=\frac{P\left(A\cap B\right)}{P\left(A\right)}\\ =\frac{0.42}{0.85}\\ =0.4941\end{array}$