Ans: A
Note that there are $28$ students in the distribution.
Note that there are $28$ students in the distribution.
The lower-quartile
$\begin{array}{cl}
= & \dfrac{\text{the 7th datum} + \text{the 8th datum}}{2} \\
= & \dfrac{5+5}{2} \\
= & 5
\end{array}$
The upper-quartile
$\begin{array}{cl}
= & \dfrac{\text{the 21st datum} + \text{the 22nd datum}}{2} \\
= & \dfrac{6 + 6}{2} \\
= & 6
\end{array}$
Hence, the inter-quartile range of the distribution
$\begin{array}{cl}
= & 6 – 5 \\
= & 1
\end{array}$
