Chapter 4, Problem AP1.6CPT

To determine

To select the best option from the multiple choice question according to the given question.

Answer to Problem AP1.6CPT

Option (c) is correct.

Explanation of Solution

The mean of the normal distribution is at the location of the peak in the ormal density curve. We note that the peak occurs roughly at $225$ on the horizontal axis and thus we estimate the mean to be roughly $225$ .

  $\mu =225$

The standard deviation is the distance from the inflection point of the normal density curve to the mean $\mu =225$ . We note that the inflection point corresponds roughly with $275$ on the horizontal axis and thus the standard deviation $\sigma$ is the difference between $275$ and the mean $\mu =225$ .

  $\begin{array}{l}\sigma =275-\mu \\ =275-225\\ =50\end{array}$

Thus, the correct option is (c) option.