Data Presentation
Pictograms and Bar Charts

Bar charts and pictograms can be used for displaying data when the data are in discrete categories.

For example, the bar chart and pictogram below show the favourite sports of 25 students.

Worked Examples

1

The pictogram shows the number of customers using a coffee shop during one week.

(a)

How many customers used the shop on Wednesday?

Show me

For Wednesday there are 5 symbols, so the number of customers was

5 × 20 = 100
(b)

How many customers used the shop on Monday?

Show me

For Monday there are symbols, so the number of customers was

× 20 = 70
(c)

How many customers visited the coffee shop during the week?

Show me

The total for the week is given by

70 + 60 + 100 + 50 + 100 + 130 = 510 customers.
2

John asked each person in the class what their shoe size was. He obtained these results.

Draw a bar chart to show this data.

Show me

First the data can be entered into a tally chart, as shown here.

The bar chart can be drawn as shown below.
3

The table below shows the number of chocolates sold by the school canteen for a given week.

(a)

How many more chocolates were sold on Friday than on Tuesday?

Show me

60 − 45 = 15. So 15 more chocolates were sold on Friday than on Tuesday.
(b)

What was the total number of chocolates sold for the week?

Show me

Total = 22 + 45 + 58 + 35 + 60 = 220 chocolates.
(c)

What was the mean number of chocolates sold daily?

Show me

(Mean is covered in detail in another unit.)

Mean =
= = 44
(d)

Draw a bar chart to show this data.

Show me
(e)

What is the probability that on a day chosen at random, less than 50 chocolates were sold?

Show me

(Probability is covered in detail in another units.)

p(no. chocolates < 50) = (= 0.6)

(The mean of a group of numbers is the average of those numbers.)

Exercises

Jenny kept a record of the average number of cans she recycled each week over a number of years.

The pictogram shows her results.

(a)

In which year did she recycle most cans?

(b)

How many cans did she recycle each week in;

(i)
2006,
(ii)
2004,
(iii)
2007?
(c)

In which year did she recycle an average of 11 cans per week?

The pictogram shows how many suitcases were sold by a store from 2003 to 2009, with one row missing.

(a)

How many cases were sold in 2004?

(b)

What is the smallest number of cases sold in a year?

(c)

What is the greatest number of cases sold in a year?

(d)

In 2008 a total of 550 cases were sold. How many suitcase symbols should appear in the missing row?

(e)

How many suitcases have been sold altogether?

The diagram shows how many ships were in Mathsland's navy in 2008 and 2009.

Use the diagram to answer these questions.

(a)

How many ships were there in Mathsland's navy in 2008?

(b)

How many ships were there in Mathsland's navy in 2009?

The bar chart below shows the shoe sizes of a group of 15-year-old boys.

(a)

How many boys are there in the group?

(b)

Comment on the shape of the bar chart, saying whether or not this is the shape you would expect.