Displaying data
Read and interpret data displays including bar charts, dot plots and line graphs. Choose the most appropriate display for a given data type.
Worked examples
Reading a value from a bar chart
Straightforward
Problem
A bar chart shows the number of books read by students over the school holidays: Alice: 6, Bob: 4, Carol: 9, David: 7. How many books did Carol read?
1
Locate the bar for Carol on the horizontal axis.
Find Carol's name along the bottom of the chart.
2
Read the height of Carol's bar from the vertical axis.
Carol's bar reaches up to 9 on the vertical axis.
Answer
Carol read 9 books.
Choosing the most appropriate display
Moderate
Problem
A student surveys 15 classmates about how many siblings they have. The responses are: 0, 1, 1, 2, 0, 3, 1, 2, 1, 0, 1, 2, 0, 1, 3. Choose the most appropriate display.
1
Identify the data type.
Number of siblings is a count (0, 1, 2, 3), so this is discrete numerical data.
2
Consider the features of the data set.
There are 15 values and the range is small (0 to 3). Each individual value should be visible.
3
Choose the most appropriate display.
A dot plot places one dot above the number line for each response. With a small range and a small data set, it clearly shows individual values and how often each occurs. A dot plot is the most appropriate choice.
Answer
Dot plot
Calculating a total from a bar chart
Challenging
Problem
A bar chart shows the number of visitors to a museum each weekday: Monday: 85, Tuesday: 60, Wednesday: 72, Thursday: 55, Friday: 98. What is the total number of visitors for the week?
1
Read each value from the bar chart.
Monday: 85, Tuesday: 60, Wednesday: 72, Thursday: 55, Friday: 98.
2
Add the values together.
3
Continue adding.
4
Continue adding.
5
Add the final value.
Answer
370 visitors in total
Practise
Q1·Straightforward
A bar chart shows the number of students who chose each fruit as their favourite: Apple: 8, Banana: 5, Orange: 11, Grapes: 4. How many students chose orange?
Explanation
The bar for orange reaches 11 on the vertical axis, so 11 students chose orange.
Q2·Straightforward
A dot plot records the shoe sizes of a group of students. The number of dots above each size is: Size 6: 3, Size 7: 5, Size 8: 4, Size 9: 2. How many students have shoe size 7?
Explanation
There are 5 dots above size 7, so 5 students have shoe size 7.
Q3·Straightforward
A line graph shows the number of ice-creams sold each day: Monday 12, Tuesday 18, Wednesday 24, Thursday 15, Friday 30. How many ice-creams were sold on Thursday?
Explanation
The point on the line graph for Thursday is at 15 on the vertical axis.
Q4·Straightforward
A bar chart shows the points scored by five teams: Red 45, Blue 38, Green 52, Yellow 29, Purple 41. How many points did the Green team score?
Explanation
The bar for Green reaches 52 on the vertical axis, so the Green team scored 52 points.
Q5·Moderate
A student surveys classmates about whether they own a dog, cat, bird, or no pet. Which display is most appropriate for this categorical data?
Explanation
Pet type is categorical data. A bar chart shows the count for each category (dog, cat, bird, none), making it the most appropriate choice.
Q6·Moderate
A weather station records the average temperature for each month of the year and wants to show how temperature changes across the year. Which display best shows this trend?
Explanation
A line graph connects data points in sequence, making it easy to see how temperature rises and falls across the months. It is the best choice for showing trends over time.
Q7·Moderate
A sports coach records the fitness test scores of 12 players. Scores are whole numbers from 1 to 10. Which display best shows all individual scores and how often each score occurs?
Explanation
A dot plot places one dot above the number line for each data value. With a small data set and a limited range, it clearly shows individual values and the frequency of each score.
Q8·Moderate
A survey of 100 people asks them to name their favourite season. The results are to be displayed so that each season's share of the total is clearly visible. Which display is most appropriate?
Explanation
A pie chart divides a circle into sectors proportional to each category's share of the total. It is the best choice for showing how a whole group is divided among categories.
Q9·Challenging
A bar chart shows the number of students absent from school each week over 5 weeks: Week 1: 3, Week 2: 7, Week 3: 5, Week 4: 4, Week 5: 6. What is the total number of absences over the 5 weeks?
Explanation
. The total number of absences over the 5 weeks is 25.
Q10·Challenging
A dot plot shows the number of goals scored by a team in each match of a season. The dots above each value are: 0 goals: 3, 1 goal: 5, 2 goals: 4, 3 goals: 2, 4 goals: 1. How many matches did the team play in total?
Explanation
. The team played 15 matches in total.
Q11·Challenging
A pie chart shows how 80 students travel to school. The sector for walking represents 25% of the pie chart. How many students walk to school?
Explanation
. Twenty students walk to school.
Q12·Challenging
A bar chart shows the number of library books borrowed each school term: Term 1: 124, Term 2: 87, Term 3: 93, Term 4: 116. How many more books were borrowed in Term 1 than in Term 2?
Explanation
. Term 1 had 37 more books borrowed than Term 2.