Question

introduction
types of data displays
you know many ways to graph and analyze data. the different types of graphs are described below.

• bar graph: bars represent the frequency of different qualitative variables that you can use to compare data.
• histogram: bars used to show the distribution of variables and represent the frequency of quantitative data that is grouped in ranges.
• dot plot: a frequency chart that is best used for small-to moderate—sized data sets where dots represent frequencies.
• stem-and-leaf plot: a table for quantitative data that is divided into \stems\ and \leaves.\
• box-and-whisker plot: a graph that divides quantitative data by quartiles and displays outliers.
• line graph: a graph that usually shows the change in data values over time.

guided instruction
choosing a data display
how do you choose a display? it depends on the data.

• qualitative data is best displayed on either a bar graph or a dot plot.
• consider the results, shown at the right, of a survey of the music preferences of a high school class.
• use the results to create a horizontal bar graph below, left. on the right, create a dot plot of the same data.

genre	# of students
country	2
hip hop	5
jazz	2
pop	7
r&b	3
rock	8

graph templates: students’ music preferences (horizontal bar graph and dot plot)

• either display appropriately represents the data. for smaller numbers, dot plots sometimes more clearly show the data.
• note that the order of the bars or rows of dots is arbitrary.

Explanation:

To solve the problem of creating the horizontal bar graph and dot plot for the students' music preferences, we follow these steps:

Creating the Horizontal Bar Graph

Step 1: Identify the categories and their frequencies

The music genres (categories) are Classical, Country, Hip Hop, Jazz, Pop, R&B, and Rock. Their respective frequencies (number of students) are 1, 2, 5, 2, 7, 3, and 8.

Step 2: Draw the horizontal bars

• For Classical: Draw a bar from 0 to 1 on the horizontal axis (since 1 student prefers Classical).
• For Country: Draw a bar from 0 to 2.
• For Hip Hop: Draw a bar from 0 to 5.
• For Jazz: Draw a bar from 0 to 2.
• For Pop: Draw a bar from 0 to 7.
• For R&B: Draw a bar from 0 to 3.
• For Rock: Draw a bar from 0 to 8.

Creating the Dot Plot

Step 1: Set up the number line

The number line should range from 0 to 10 (since the maximum number of students for a genre is 8).

Step 2: Plot the dots for each genre

• Classical: Place 1 dot above the number 1.
• Country: Place 2 dots above the number 2.
• Hip Hop: Place 5 dots above the number 5.
• Jazz: Place 2 dots above the number 2.
• Pop: Place 7 dots above the number 7.
• R&B: Place 3 dots above the number 3.
• Rock: Place 8 dots above the number 8.

Final Visuals

• Horizontal Bar Graph: The bars for each genre will have lengths corresponding to their frequencies (1 for Classical, 2 for Country, 5 for Hip Hop, 2 for Jazz, 7 for Pop, 3 for R&B, 8 for Rock) on the horizontal axis, with the genres listed vertically.
• Dot Plot: Dots will be stacked above the numbers on the horizontal axis (0 - 10) corresponding to the number of students for each genre (e.g., 8 dots above 8 for Rock, 7 dots above 7 for Pop, etc.).

Example of the Horizontal Bar Graph (Textual Representation)

Genre	Length of Bar (from 0 to frequency)
Country	2
Hip Hop	5
Jazz	2
Pop	7
R&B	3
Rock	8

Example of the Dot Plot (Textual Representation)

• Above 1: •
• Above 2: • • (for Country) and • • (for Jazz)
• Above 3: • • •
• Above 5: • • • • •
• Above 7: • • • • • • •
• Above 8: • • • • • • • •

For the horizontal bar graph, each bar's length matches the number of students for the genre. For the dot plot, the number of dots above each number on the axis matches the frequency of the corresponding genre.

Answer:

To solve the problem of creating the horizontal bar graph and dot plot for the students' music preferences, we follow these steps:

Creating the Horizontal Bar Graph

Step 1: Identify the categories and their frequencies

The music genres (categories) are Classical, Country, Hip Hop, Jazz, Pop, R&B, and Rock. Their respective frequencies (number of students) are 1, 2, 5, 2, 7, 3, and 8.

Step 2: Draw the horizontal bars

• For Classical: Draw a bar from 0 to 1 on the horizontal axis (since 1 student prefers Classical).
• For Country: Draw a bar from 0 to 2.
• For Hip Hop: Draw a bar from 0 to 5.
• For Jazz: Draw a bar from 0 to 2.
• For Pop: Draw a bar from 0 to 7.
• For R&B: Draw a bar from 0 to 3.
• For Rock: Draw a bar from 0 to 8.

Creating the Dot Plot

Step 1: Set up the number line

The number line should range from 0 to 10 (since the maximum number of students for a genre is 8).

Step 2: Plot the dots for each genre

• Classical: Place 1 dot above the number 1.
• Country: Place 2 dots above the number 2.
• Hip Hop: Place 5 dots above the number 5.
• Jazz: Place 2 dots above the number 2.
• Pop: Place 7 dots above the number 7.
• R&B: Place 3 dots above the number 3.
• Rock: Place 8 dots above the number 8.

Final Visuals

• Horizontal Bar Graph: The bars for each genre will have lengths corresponding to their frequencies (1 for Classical, 2 for Country, 5 for Hip Hop, 2 for Jazz, 7 for Pop, 3 for R&B, 8 for Rock) on the horizontal axis, with the genres listed vertically.
• Dot Plot: Dots will be stacked above the numbers on the horizontal axis (0 - 10) corresponding to the number of students for each genre (e.g., 8 dots above 8 for Rock, 7 dots above 7 for Pop, etc.).

Example of the Horizontal Bar Graph (Textual Representation)

Genre	Length of Bar (from 0 to frequency)
Country	2
Hip Hop	5
Jazz	2
Pop	7
R&B	3
Rock	8

Example of the Dot Plot (Textual Representation)

• Above 1: •
• Above 2: • • (for Country) and • • (for Jazz)
• Above 3: • • •
• Above 5: • • • • •
• Above 7: • • • • • • •
• Above 8: • • • • • • • •

For the horizontal bar graph, each bar's length matches the number of students for the genre. For the dot plot, the number of dots above each number on the axis matches the frequency of the corresponding genre.