For Rachel's history project she wants to create a graph that illustrates the population growth (in millions) of the countries listed in the table below.

Country |
1980 |
1990 |
2000 |

France | 55 | 56 | 65 |

United Kingdom | 50 | 53 | 63 |

Mexico | 65 | 78 | 80 |

Nigeria | 60 | 82 | 85 |

Pakistan | 57 | 65 | 74 |

How can Rachel create a graph to illustrate the data over time?

In this concept, you will learn how to create and read multiple bar graphs.

### Creating and Reading Multiple Bar Graphs

**Data** is a set of numerical or non-numerical information. Data can be analyzed in many different ways. In this concept you will analyze numerical data using multiple bar graphs.

One way to display data is in a **multiple bar graph.** A multiple bar graph shows the relationship between different values of data. Each data value is represented by a column in the graph. In a multiple bar graph, multiple data points for each category of data are shown with the addition of columns. The categories of different kinds of data are listed along the horizontal, or *x*, axis. The quantity or amount of data is listed along the vertical, or *y*, axis. Lastly, the legend, or key, states what each column represents.

Let's look at an example.

Frank's Farm Stand kept track of the number of pounds of vegetables sold over a three-day period. The results are listed on the table below. Create a multiple bar graph to display the data. Then, list three conclusions that can be made about the data.

Type of Vegetable: |
Pounds Sold: Day One |
Pounds Sold: Day Two |
Pounds Sold: Day Three |
---|---|---|---|

Squash | 32 lbs. | 36 lbs. | 36 lbs. |

Zucchini | 40 lbs. | 33 lbs. | 37 lbs. |

Corn | 56 lbs. | 65 lbs. | 67 lbs. |

Carrots | 28 lbs. | 25 lbs. | 23 lbs. |

Romaine Lettuce | 27 lbs. | 31 lbs. | 34 lbs. |

Tomatoes | 44 lbs. | 54 lbs. | 58 lbs. |

First, create the multiple bar graph. To do this, draw the horizontal (*x*) and vertical (*y*) axes.

Next, label the vertical axis. The vertical axis lists the quantity or amount of the data. In this case, the category will be "Pounds Sold."

Next, title the graph. The title of the graph should be short and clear. It should explain what data is presented in the graph. In this case, the title will be “Amount of Vegetables Sold at Frank's Farm Stand.”

Then, determine the units on the vertical axis. To do this, start by reviewing the smallest and largest values in the table. The smallest value is 23 and the largest is 65. Based on these values label the vertical axis from 0-70. Since the values are whole numbers and are relatively spread out, a unit of 10 can be used. Therefore, the vertical axis will start at 0 and go to 70 by increments of 10.

Next, draw the vertical columns. To do this, write each type of vegetable along the horizontal axis, leaving space between each one. Each type of vegetable will have three columns, one for each day. These should be drawn in different colors. To start, draw the amount of squash sold on day one. To do this draw a column vertically until it reaches the quantity 32. Then draw the amount of squash sold on day two. To do this draw the column vertically until it reaches 36. Complete the columns for squash by drawing the amount for day three, 36, in a vertical column. Continue this pattern for the other vegetables.

Next, create the legend, or key. Each column for each category represents a different day. The legend must represent this by denoting which color is for day one, day two, and day three.

Finally, state three conclusions from the graph. To do this, analyze the data presented in the table by comparing the heights of the bars.

The first answer is the graph should look like the one below. The second answer is three conclusions that can be made from the graph are: corn was the vegetable that sold the greatest amount each day; the amount of carrots decreased each day from days one to three; and squash, corn, romaine lettuce, and tomatoes saw an increase in amounts sold across each day.

### Examples

#### Example 1

Earlier, you were given a problem about Rachel and her graph.

Rachel wants to create a graph that displays the population growth (in millions) in the table below.

Country |
1980 |
1990 |
2000 |

France | 55 | 56 | 65 |

United Kingdom | 50 | 53 | 63 |

Mexico | 65 | 78 | 80 |

Nigeria | 60 | 82 | 85 |

Pakistan | 57 | 65 | 74 |

First, Rachel will create a multiple bar graph because there are multiple years of data for each country. To do this, she will draw the horizontal and vertical axes.

Next, she will label the horizontal axis. The horizontal axis lists the different categories of data. In this case, the category will be "Country."

Next, she will label the vertical axis. The vertical axis lists the quantity or amount of the data. In this case, the category will be "Population (in millions)."

Next, she will title the graph. The title of the graph should be short and clear. It should explain what data is presented in the graph. In this case, the title will be “Population.”

Then, she will determine the units on the vertical axis. To do this, start by reviewing the smallest and largest values in the table. The smallest value is 50 and the largest is 85. Based on these values label the vertical axis from 0-90. Since the values are whole numbers and relatively spread out, a unit of 10 can be used. Therefore, the vertical axis will start at 0 and go to 90 by increments of 10. (Remember that the values are in millions.)

Next, draw the vertical columns. To do this, write each country along the horizontal axis, leaving space between each one. Each country will have three columns, one for each year. These should be drawn in different colors. To start, draw the population for France in 1980. To do this draw a column vertically until it reaches the quantity 55. Then draw the population for 1990 and 2000. To do this draw the column vertically until it reaches 56 and 65 respectively. Continue this pattern for the remaining countries.

Next, create the legend, or key. Each column for each country represents a different year. The legend must represent this by denoting which color is for 1980, 1990, and 2000.

The answer is the graph should look like the one below.

#### Example 2

The graph below shows the populations of the major cities in UAE in years 1995 and 2003. List three conclusions that can be made from the graph.

First, analyze the graph by comparing the heights of the columns.

The answer is three conclusions that can be made from the graph are: Dubai has the largest population in both years, 1995 and 2003; Dubai saw the greatest increase in population from years 1995 to 2003; and all cities saw a growth in population from years 1995 to 2003.

#### Example 3

The table below shows the World Health Organization's estimated number of diabetes cases. Create a bar graph to display the data from the table. Then, state three conclusions that can be made about the data.

Country |
2000 Estimate |
2030 Estimate |

Antigua and Barbuda | 3000 | 5000 |

Cook Islands | 700 | 1300 |

Marshall Islands | 2000 | 4000 |

Monaco | 2000 | 3000 |

Nauru | 2000 | 4000 |

Palau | 1000 | 2000 |

Saint Kitts and Nevis | 2000 | 2000 |

San Marino | 2000 | 3000 |

Sao Tome-Principe | 1000 | 2000 |

Tuvalu | 300 | 800 |

First, create the multiple bar graph. To do this, draw the horizontal (*x*) and vertical (*y*) axes.

Next, label the vertical axis. The vertical axis lists the quantity or amount of the data. In this case, the category will be "Number of Cases."

Next, title the graph. The title of the graph should be short and clear. It should explain what data is presented in the graph. In this case, the title will be “WHO Estimated Diabetes Cases for 2000 and 2030.”

Then, determine the units on the vertical axis. To do this, start by reviewing the smallest and largest values in the table. The smallest value is 300 and the largest is 5000. Based on these values label the vertical axis from 0-5000. Since the values are whole numbers and relatively spread out, a unit of 500 can be used. Therefore, the vertical axis will start at 0 and go to 5000 by increments of 500.

Next, draw the vertical columns. To do this, write each country along the horizontal axis, leaving space between each one. Each country will have two columns, one for each year. These should be drawn in different colors. To start, draw the number of cases for Antigua and Barbuda for 2000. To do this draw a column vertically until it reaches the quantity 3000. Then draw the number of cases for 2030. To do this draw the column vertically until it reaches 5000. Continue this pattern for the remaining countries.

Next, create the legend, or key. Each column for each country represents a different year. The legend must represent this by denoting which color is for 2000 and 2030.

Finally, state three conclusions from the graph. To do this, analyze the data presented in the table by comparing the heights of the bars.

The first answer is the graph should look like the one below. The second answer is three conclusions that can be made from the graph are: Saint Kitts and Nevis did not see an increase in the number of diabetes cases between 2000 and 2030; Antigua and Barbuda has the greatest number of estimated cases for 2030; and Tuvalu has the smallest number of estimated cases for both years 2000 and 2030.

#### Example 4

The graph below shows the number of mobile phone subscribers for the years 2006, 2007, and 2009. List three conclusions that can be made from the graph.

First, analyze the graph by comparing the heights of the columns.

The answer is three conclusions that can be made from the graph are: all countries had over 7 million subscribers in 2009; all countries saw an increase in the number of mobile phone subscribers from years 2007 to 2009; and the USA saw a decline in the number of subscribers from 2006 to 2007.

#### Example 5

The graph below shows the number of university students enrolled in business majors in Saudi Arabia, Kuwait, and Qatar. List two conclusions that can be made from the graph.

First, analyze the graph by comparing the heights of the columns.

The answer is two conclusions that can be made from the graph are: Saudi Arabia saw a decrease in the number of business majors in years 2003 to 2005 and from 2006 to 2007; and Qatar saw an increase in the number of business majors between the years 2003 to 2004 and 2005 to 2007.

### Review

The multiple bar graph below depicts the number of Major League Baseball teams in each state, as well as the number of World Series Championships won by each state. Use the graph to answer the questions.

- How many Major League Baseball teams are represented on the graph? _____
- How many World Championships are represented on the graph? _____
- How many of states on the graph have won a Major League Championship? _____
- Which states have equal numbers of Major League Baseball teams? _____
- Which state has won the greatest number of World Championships? _____

Directions: Twenty students in , , and grade were asked to state how many of each of the following electronic devices their homes contained.

- Create a multiple line graph to display the information from the table.

Name of Device: |
Grade Answers: |
Grade Answers: |
Grade Answers: |
---|---|---|---|

Television | 35 | 28 | 31 |

DVD Player | 30 | 28 | 20 |

Computer | 19 | 20 | 17 |

Game System | 15 | 14 | 20 |

Video Camera | 14 | 17 | 12 |

- What is the most common electronic device in the sixth grade?
- What is the most common electronic device in the seventh grade?
- What is the most common electronic device in the eighth grade?
- What is the least common electronic device in the sixth grade?
- What is the least common electronic device in the seventh grade?
- What is the least common electronic device in the eighth grade?
- What is the difference between the number of sixth graders who watch tv and the number of seventh graders?
- What is the difference between the number of seventh graders who watch tv and the number of eighth graders?
- True or false. For computer use, seventh graders have the highest number.

### Review (Answers)

To see the Review answers, open this PDF file and look for section 11.6.