Chapter 2.1, Problem 11E

a.

To determine

To find: The interquartile range of the provided distribution.

Explanation of Solution

Given:

The plot is:

  

From the provided plot, the third quartile and first quartile are 12.75 and 3.75 respectively.

Thus, the interquartile range is:

  $\begin{array}{c}IQR=Q_3-Q_1\\ =12.75-3.75\\ =9.00\end{array}$

Thus, the required value is 9.00

b.

To determine

To find: The percentile of Arizona.

Answer to Problem 11E

The percentile is 84.

Explanation of Solution

To compute the required percentage construct a vertical line that cuts the x -axis at 15.1. Now, construct a horizontal line for the intersection of the vertical line.

It could be seen that both the line intersecting at 84^th percentile.

Thus, the required percentile is 84.

c.

To determine

To explain: The reason of curve being flat between 20% and 27.5%.

Explanation of Solution

Here, the cumulative relative frequency is increasing between the values $20\%$ and $27.5\%$ because of the slight increase in the frequency for these values.

d.

To determine

To construct: The histogram corresponds to the provided figure.

Explanation of Solution

The histogram could be constructed as: