Chapter 12.5, Problem 17HP

To determine

Find the number of players in the case.

Answer to Problem 17HP

  $1600$ .

Explanation of Solution

Given information:

A case of digital audio players has an average battery life of $8$ hours with standard deviation of $0.7hour$ . $8$ of the players have battery life greater than $10.1hour$ . If the sample is normally distributed .

Calculation:

There is only $0.5\%$ chance of values being greater than $10.1$ ,

  $\begin{array}{l}0.5\%\times x=8\\ x=\frac{8\times 1000}{5}\\ x=1600\end{array}$

Hence, the number of players in the case is $1600$ .