Exercise 5 Page 506

Quartiles are values that divide a data set into four equal parts.

• The median, which can also be known as the second quartile (Q_2), separates the data into upper and lower halves.
• The first quartile (Q_1) is the median of the lower half of the data.
• The third quartile (Q_3) is the median of the upper half of the data.

  Let's identify quartiles of the given data set. Do not forget to arrange the data from least to greatest first!

  

  The first quartile is 13 and the third quartile is 30. The median of the data is 19. Finally, we can use the values of the first and third quartiles to find the interquartile range (IQR). Q_3-Q_1=IQR ⇓ 30 - 13 = 17