Chapter 10.1, Problem 3E

(a)

To determine

To Calculate: the probability

Answer to Problem 3E

  $\text{P}\left(z<-2.03\right)=0.2118$

Explanation of Solution

Given:

From previous exercise

  $\begin{array}{c}\mu =0.15\\ \sigma =0.07399\end{array}$

Formula used:

  $z=\frac{x-\mu }{\sigma }$

Calculation:

  $\begin{array}{c}z=\frac{x-\mu }{\sigma }\\ =\frac{0-0.15}{0.07399}\\ =-2.03\end{array}$

  

  $\begin{array}{c}\text{P}\left(z<-2.03\right)=0.2118\\ =2.118\%\end{array}$

(b)

To determine

To Explain: the reason of company’s claim about doubt

Explanation of Solution

Since the probability is $\text{P}\left(z<-2.03\right)=2.118\%$ which is very small, this would gives the reason to doubt the company’s claim