Chapter B.2, Problem 36E

a.

To determine

To find : The lower and upper quartiles of the data.

Answer to Problem 36E

The lower quartile is $21$ and the upper quartile is $28$ .

Explanation of Solution

Given: The given data is $25,20,22,28,24,28,25,19,27,29,28,21$ .

Calculation:

The given data is $25,20,22,28,24,28,25,19,27,29,28,21$ .

Data in asecending order

  $19,20,21,22,24,25,25,27,28,28,28,29$

This set has $12$ member .

The median of entire set is $\frac{25+25}{2}=\frac{50}{2}=25$ .

The median of the five number that are before $25$ is $21$ . So the lower quartile is $21$ .

The median of the three number that are after $25$ is $28$ . So the upper quartile is $28$ .

b.

To determine

To sketch:A box and whisker plot for the data without using graphing utility.

Answer to Problem 36E

Box and whisker plot is :

  

Explanation of Solution

Given: The given data is $25,20,22,28,24,28,25,19,27,29,28,21$ .

Calculation:

The given data is $25,20,22,28,24,28,25,19,27,29,28,21$ .

Data in asecending order

  $19,20,21,22,24,25,25,27,28,28,28,29$

This set has $12$ member .

The median of entire set is $\frac{25+25}{2}=\frac{50}{2}=25$ .

The median of the five number that are before $25$ is $21$ . So the lower quartile is $21$ .

The median of the three number that are after $25$ is $28$ . So the upper quartile is $28$ .

Box and whisker plot is :