Warm-Up Jan. 27• Is this data quantitative or categorical?

Different Types of Graphs

Doris Spencer

Tables, charts and graphs are convenient ways to clearly show your data.

Purpose of Graphs

• To analyze data it is easier to use graphs and numerical summaries.

• They are the best tools for describing patterns in the data, as well as any deviations from those patterns.

Day Chocolate Strawberry White

Monday 53 78 126

Tuesday 72 97 87

Wednesday 112 73 86

Thursday 33 78 143

Friday 76 47 162

The cafeteria wanted to collect data on how much milk was sold in 1 week. The table below shows the results. We are going to take this data and display it in 3 different types of graphs.

Circle (or Pie) Graph

There are three basic graph forms.

Notice how each of the following examples are used to illustrate the data.

Choose the best graph form to express your results.

Bar Graph

Line Graph

Bar Graph• A bar graph is used to show

relationships between groups.• The two items being compared

do not need to affect each other.• It's a fast way to show big

differences. Notice how easy it is to read a bar graph. Chocolate Milk Sold

53

72

112

33

76

0

20

40

60

80

100

120

Monday Tuesday Wednesday Thursday Friday

Day

Am

ount

Sol

d

Monday TuesdayWednesday ThursdayFriday

Circle Graph or Pie Graph

• A circle graph is used to show how a part of something relates to the whole.

• This kind of graph is needed to show percentages effectively.

Chocolate Milk Sold

Monday

Tuesday

Wednesday

Thursday

Friday

21%

28%

41%

13%

27%

Chocolate MI lk Sold

0

20

40

60

80

100

120

Monday Tuesday Wednesday Thursday Friday

Day

Am

ount

Sol

d

Chocolate

Chocolate Milk Sold

Monday

Tuesday

Wednesday

Thursday

Friday

Bar Graph

Line Graph

Circle (Pie) Graph

The same data displayed in 3 different

types of graphs.

Chocolate Milk Sold

53

72

112

33

76

0

20

40

60

80

100

120

Monday Tuesday Wednesday Thursday Friday

Day

Am

ount

Sol

d

Monday TuesdayWednesday ThursdayFriday

On what day did they sell the most chocolate milk?

Chocolate Milk Sold

53

72

112

33

76

0

20

40

60

80

100

120

Monday Tuesday Wednesday Thursday Friday

Day

Am

ount

Sol

d

Monday TuesdayWednesday ThursdayFriday

Chocolate

Monday

Tuesday

Wednesday

Thursday

Friday

On what day was the least amount of chocolate milk sold?

If there are 1150 students in the school how many students bought chocolate milk on Wednesday?

21%

28%

41%

13%

27%

Choosing the Right Graph

• Use a bar graph if you are not looking for trends (or patterns) over time; and the items (or categories) are not parts of a whole.

• Use a pie chart if you need to compare different parts of a whole, there is no time involved and there are not too many items (or categories). • Use a line graph if you need to see how a quantity has changed over time.  Line graphs enable us to find trends (or patterns) over time.

Step 1: To get data you have to first poll and ask a question of interest.

Our question of interest is going to be do you have tattoos? ( yes or no responses )

This can best be graphed in a pie chart.

Yes No

Our next question is going to be who has tattoos?

• This type of data can be graphed in a bar graph.

Males Females

Out of the data we collected, which ones can be represented by

a pie chart, or bar graph?• Do you plan on attending college?

• How old are you?

• Do you have a job?

• Where do you work?

• How tall are you?

• What is your favorite color?

• What is your favorite place to shop?

• What is your favorite food?

Homework

• Worksheet