A grouped distribution of weekly screen–time of teenagers is given below. One class frequency is missing.
Class interval (hours): 0–10 10–20 20–30 30–40 40–50
Frequency: 6 9 x 12 8
The median screen–time is known to be 27.5 hours. Answer the following.
(i) Identify the median class for the above distribution and state its lower class boundary.
(ii) Determine the missing frequency x that satisfies the given median value.
(iii) Verify your answer by recalculating the median with the value of x obtained in part (ii).