The intercuartil is the zone that have 50% of the points so first we have to calculate the mean that will be:
[tex]\begin{gathered} \mu=\frac{1+2+3+3+4+4+4+6}{8} \\ \mu=3.37 \end{gathered}[/tex]Now we calculate the Q1 quartuile 1 the will be:
[tex]\begin{gathered} Q1=\frac{1}{4}(8+1) \\ Q1=2.25 \end{gathered}[/tex]and the Q3 quartile 3 will be:
[tex]\begin{gathered} Q3=\frac{3}{4}(8+1) \\ Q3=6.75 \end{gathered}[/tex]and the interquartile will be:
[tex]\begin{gathered} \text{IQR}=6.75-2.25 \\ \text{IQR}=4.5 \end{gathered}[/tex]