A student was asked to display the following grouped data for the ages of 50 people in a community centre:
Class intervals (years): 10–14, 14–18, 18–22, 22–26, 26–30
Frequencies: 4, 11, 18, 9, 8
The student drew a graph with five separated rectangles of equal width, leaving identical gaps between consecutive rectangles, and labelled the vertical axis as "Number of People".
Respond to the tasks below:
(i) Identify and describe two specific errors in the way the student has represented the data.
(ii) Describe, step by step, how you would correct the graph so that it accurately reflects the given distribution.
(iii) Justify, with clear reasoning, why adjacency of rectangles and consideration of area are essential when graphing this particular data set.