- A teacher recorded, to the nearest hour, the time spent watching television during a particular week by each child in a random sample. The times were summarised in a grouped frequency table and represented by a histogram.
One of the classes in the grouped frequency distribution was 20-29 and its associated frequency was 9. On the histogram the height of the rectangle representing that class was 3.6 cm and the width was 2 cm .
- Give a reason to support the use of a histogram to represent these data.
- Write down the underlying feature associated with each of the bars in a histogram.
- Show that on this histogram each child was represented by \(0.8 \mathrm {~cm} ^ { 2 }\).
The total area under the histogram was \(24 \mathrm {~cm} ^ { 2 }\).
- Find the total number of children in the group.