Given:
Given the data set
6, 6, 6, 7, 8, 9, 9, 10, 11, 12, 12, 13, 14, 15, 18
Required: Interquartile range
Explanation:
Sample size is n = 15.
First, arrange the data set in ascending order.
6, 6, 6, 7, 8, 9, 9, 10, 11, 12, 12, 13, 14, 15, 18
Compute the quartiles Q1 and Q3.
![\begin{gathered} Q_1=((n+1)/(4))^{t\text{h }}\text{ term} \\ =((15+1)/(4))^(th)\text{ term} \\ =4^(th)\text{ term} \\ =7 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/7wrgdcb584rhgqbl9f8am0tac2l9xtc32r.png)
![\begin{gathered} Q_3=((3(n+1))/(4))^(th)\text{ term} \\ =((3(15+1))/(4))^(th)\text{ term} \\ =12^(th)\text{ term} \\ =13 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/bgp4dau0j1td43hr2xsbapon613bdg7tlm.png)
The interquartile range is
![\begin{gathered} IQR=Q_3-Q_1 \\ =13-7 \\ =6 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/cy9hzxu3vxlebett28tv10ftnhdmnsj7p3.png)
Final Answer: The interquartile range of the given data set is 6.