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# Bar graphs review

Bar graphs are a nice way to visualize categorical data. This article reviews how to create and read bar graphs.
A bar graph is a nice way to display categorical data.
For example, imagine a P.E. teacher has $4$ soccer balls, $4$ footballs, $7$ tennis balls, and $8$ volleyballs. We can display this data in a bar graph:
Notice how the height of the bar above "soccer" is $4$ units to show that there are $4$ soccer balls. And the bar above "tennis" is $7$ units high to show that there are $7$ tennis balls. The "football" and "volleyball" bars work in the same way.

## Practice set 1: making bar graphs

Problem 1.A
There are $4$ purple, $5$ yellow, $2$ green, and $9$ red lunch boxes.
Make a bar graph for this data.

Want to practice more problems like these? Check out this exercise.

## Practice set 2: reading bar graph

Problem 2.A
The music store sells trumpets, flutes, and drums.
This bar graph shows how many of each instrument are at the store.
How many more trumpets are there than flutes?
more trumpets

Want to practice more problems like these? Check out this exercise and this more advanced exercise.

## Want to join the conversation?

• What is a parallel modified boxplot?
• Comparing several box plots on the same scale and then taking conclusions out of them.
• How to create Parallel modified boxplot
• Why wasn't there a practice section for "Reading bar charts: Putting it together with central tendency?"
• in an example where the capacity of the car and number of seats given. shouldnt both be categorical instead of quantitative as there are fixed categories of cars based on number of seats either 2,4,5,6,7 and similarly the capacity is also categorized likewise.
• No, they won't be called categorical because the difference between categorical and quantitave data boils to the simple rule whether we can perform valid arithmetic operations on it. For example the no of seats can be 2,4,5,6,7 (True) but you can perform arithmetic operations(addition on it) eg 2 seats + 2seats is 4 seats which makes perfect sense. So it is a quantitative variable in principle.
However, suppose there is another variable called color of the car. Now color can be RED BLACK or Blue.
In this case performing an arithmetic operation doesn't make sense :
RED + BLACK doesn't make valid sense.
So color of the car is a qualitative/categorical variable
• does this txt thing work
• if a mean test mark is 3 , what would be the value