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## Statistics and probability

### Course: Statistics and probability > Unit 1

Lesson 1: Analyzing one categorical variable- Identifying individuals, variables and categorical variables in a data set
- Individuals, variables, and categorical & quantitative data
- Reading pictographs
- Read picture graphs (multi-step problems)
- Reading bar graphs
- Reading bar graphs: Harry Potter
- Creating a bar graph
- Create bar graphs
- Reading bar charts: comparing two sets of data
- Read bar graphs (2-step problems)
- Reading bar charts: putting it together with central tendency
- Reading pie graphs (circle graphs)
- Picture graphs (pictographs) review
- Bar graphs review

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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.

*Want to learn more about bar graphs? Check out this video.*

## Practice set 1: making bar graphs

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

## Practice set 2: reading bar graph

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?(16 votes)
- Comparing several box plots on the same scale and then taking conclusions out of them.(16 votes)

- How to create Parallel modified boxplot(16 votes)
- Why wasn't there a practice section for "Reading bar charts: Putting it together with central tendency?"(10 votes)
- 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.(2 votes)
- 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(8 votes)

- does this txt thing work(4 votes)
- if a mean test mark is 3 , what would be the value(4 votes)
- What has been called here categorical data, has been called quantitative data in the first video of this unit. Just saying..(0 votes)
- Nope, these are different. Quantitative represents something whose numeric value matters such as age, height, growth, etc. Qualitative is describing the frequency of something with not mathematical values such as color or weather.(5 votes)

- this is to easy(1 vote)
- sir can you explain more on pie chart(1 vote)
- I think that the pie chart is another way to represent data, to show numbers. Something I like about it is that it would be easy to see the highest amount of something when you are eyeballing it, although can't really say the same for the least amount of something sometimes.(1 vote)