The height of each bar in a histogram is called the frequency density. This is calculated as: frequency density = frequency divided by class width. This method is summarised here.
Here’s the GCSE questions we did in class.
The answers are below. Make sure you
understand how to work out the mean in question 2, if you’re not sure then ask
me to explain.
If you got all these right, try this extension question:
A histogram was drawn to show the distribution of age in
completed years of the participants on an outward-bound course. There were 32 people aged 30-34 years on the
course. The height of the rectangle representing this group was 19.2 cm and it
was 1 cm in width. Given that there 28
people aged 35-39 years, find the height of the rectangle representing this
group . Given that the height of the rectangle representing people aged 40-59
years was 2.7 cm, find the number of people on the course in this age group.
Classwork answers: 1b) 100 2a) 100 b) 51.9 3) The missing frequencies are: 17 and 28 4) 110 members 5) The missing frequencies are: 30 and 60 6a) The missing frequencies are: 21 and 33. b) T = 64 7a) 90 b) 22cm c) 14.75cm 8b) 735 minutes.