Answer: The correct option is
(A) The mean of the 9th and 10th values.
Step-by-step explanation: Given that there are 18 values in a data set in order from smallest to largest.
We are to find the median of the data set.
We know that
if a data set has n values, then the median value is given by
\((i)~\dfrac{n+1}{2},\) if n is odd.
\((ii)\textup{the mean of }\dfrac{n}{2}~\textup{and}~\dfrac{n}{2}+1\) if n is even.
In the given situation, we have
n = 18, which is even.
So, the median values are given by the mean of
\(\dfrac{18}{2},~~\dfrac{18}{2}+1\\\\=9,~~10.\)
Therefore, the required median value is the mean of 9th and 10th values.
Option (A) is CORRECT.
