2.4.1 Try some yourself
Activity 13
The frequency diagram below shows the numbers of people in different age groups in a sample of the UK population.
(a) What is the width of each age group?
(b) Which age group contains the largest number of people?
Answer
(a) The width of each age group is 10 years. For example, the ten ages 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 years make up the first age group.
(b) The largest number of people are in the age group 10 and above but less than 20 years.
Activity 14
The bar chart below represents the numbers of cars predicted to be sold by one company in nine successive years.
(a) How many cars were predicted to be sold in 2010?
(b) How many cars were predicted to be sold in 2015?
(c) What does the bar chart suggest about the pattern of predicted sales?
Answer
(a) About 12 000.
(b) About 21 000.
(c) Generally the sales figures are increasing, although there was a slight fall in 2012.
Activity 15
This table summarises the results of a survey of 300 people who were asked how long it took them to get from Central London to Heathrow Airport.
| Time/mins | Number of people |
|---|---|
| 30–35 | 30 |
| 35–40 | 60 |
| 40–45 | 110 |
| 45–50 | 50 |
| 50–55 | 30 |
| 55–60 | 10 |
| 60–65 | 10 |
| Total | 300 |
(a) Illustrate the information by means of a frequency diagram. (You may find it easiest to draw your frequency diagram on graph paper.)
(b) What does the width of each interval represent?
Answer
(a)
(b) The width of each interval represents 5 minutes of journey time.