Maharashtra Board Class 7 Maths part 1 Chapter 7 Joint Bar Graph PDF Download

Joint Bar Graph

Observe the two bar graphs below which show the wheat production in quintals in Ajay's and Vijay's farms.

Let us see if we can show the information from both graphs in a single graph. Look at the graph below. In this way, more information can be given using less space. Besides, comparing Ajay and Vijay's wheat production also becomes easier. Such graphs are called joint bar graphs.

Observe the graph shown alongside and answer the following questions.

In which year did they both produce equal quantities of wheat?

In year 2014, who produced more wheat?

In year 2013, how much wheat did Ajay and Vijay each produce?

Teacher's Note

A joint bar graph shows two types of information at the same time. For example, you can see the rice production of two farmers in one graph instead of two separate graphs.

Exam Trick

Remember: Joint bar graph = two bar graphs combined into one. Look for the legend (the small box with colors) to know which bar is for which person.

Points to Remember

A joint bar graph shows two sets of data together.
Different colors are used for different bars.
The legend tells you what each color means.
You can compare two things easily in a joint bar graph.

Reading A Joint Bar Graph

The minimum and maximum temperature in Pune for five days is given. Read the joint bar graph and answer the questions below.

What data is shown on X-axis?

What data is shown on Y-axis?

Which day had the highest temperature?

On which day is the minimum temperature the highest?

On Thursday, what is the difference between the minimum and maximum temperature?

On which day is the difference between the minimum and maximum temperature the greatest?

Teacher's Note

Reading a joint bar graph is like reading two graphs at once. Just look at both bars in each pair and compare their heights to answer questions.

Exam Trick

Always check the legend first. Then find the day or group you need. Compare the height of both bars to find the answer.

Points to Remember

X-axis shows the categories or time periods.
Y-axis shows the numbers or quantities.
Read the scale carefully before answering questions.
Always use the legend to understand which bar means what.

Drawing A Joint Bar Graph

The number of boys and girls in a school is given. Draw a joint bar graph to show this information.

Steps For Drawing A Joint Bar Graph

On a graph paper, draw the X-axis and Y-axis and their point of intersection.

Keeping the distance between two sets of joint bars equal, show the classes on X-axis.

Choose a scale for the Y-axis. For example, 1 unit = 10 girls/boys. Mark the numbers of boys and girls on the Y-axis.

Using the scale, work out the height of columns required to show the numbers of boys and girls in each class. Use different colours to show the different bars in each set.

Teacher's Note

When drawing a joint bar graph, always keep equal space between the two bars in each pair. Use two different colors so students can see the difference clearly.

Exam Trick

Draw lightly with a pencil first. Then use a scale (ruler) to make the bars straight. Use different colors or patterns to show which bar is for boys and which is for girls.

Points to Remember

All columns must have equal width.
Space between bars in each pair must be equal.
Always use a scale that is easy to work with.
Use different colors for different bars.
Always write a legend or key for your graph.

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