Interpreting pie charts and frequency diagrams
Example 1
The pie chart below shows the heights (in \(cm\)) of 30 pupils in a class.
The biggest slice of the pie chart contains the most people: \( 151 - 160cm\).
Question
How many pupils are between \(121 - 130cm\) tall?
The angle of this sector is \(36^{\circ}\).
The question says there are 30 pupils in the class so, the number of pupils of height \(121 - 130 cm \) is:
\(\frac{{36}}{{360}} \times 30 = 3\)
Example 2
A survey was conducted to determine the number of people in cars during rush hour.
The results are shown in the frequency diagram below.
Question
What is the total number of cars in the survey?
\(6 + 3 + 5 + 1 = 15\)
There are 6 cars with one person, 3 cars with two people, 5 cars with three people, and 1 car with four people.
Question
What is the most likely number of people in a car?
Cars in the survey are most likely to have 1 person in them as this is the tallest bar - 6 of the cars in the survey had one occupant.
