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

two graph templates: left is \students music preferences\ horizontal bar graph with y-axis labels (rock, r&b, pop, jazz, hip hop, country, classical) and x-axis 0–10. right is dot plot with same y-axis and x-axis 0–10.

• 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 create the horizontal bar graph and dot plot for the students' music preferences data:

Horizontal Bar Graph (Left)

1. Axes Setup: The vertical axis lists the music genres (Classical, Country, Hip Hop, Jazz, Pop, R&B, Rock) in order from bottom to top (or top to bottom as per the given layout). The horizontal axis is a number line from 0 to 10, representing the number of students.
2. Drawing Bars:

• For "Classical" with 1 student: Draw a horizontal bar starting from the "Classical" label on the vertical axis, extending to 1 on the horizontal axis.
• For "Country" with 2 students: Draw a bar extending to 2.
• For "Hip Hop" with 5 students: Draw a bar extending to 5.
• For "Jazz" with 2 students: Draw a bar extending to 2.
• For "Pop" with 7 students: Draw a bar extending to 7.
• For "R&B" with 3 students: Draw a bar extending to 3.
• For "Rock" with 8 students: Draw a bar extending to 8.

Dot Plot (Right)

1. Axes Setup: The vertical axis lists the music genres (same order as the bar graph). The horizontal axis is a number line from 0 to 10, representing the number of students.
2. Plotting Dots:

• For "Classical" (1 student): Place 1 dot above the "Classical" label at the position corresponding to 1 on the horizontal axis.
• For "Country" (2 students): Place 2 dots above "Country" at the position corresponding to 2.
• For "Hip Hop" (5 students): Place 5 dots above "Hip Hop" at the position corresponding to 5.
• For "Jazz" (2 students): Place 2 dots above "Jazz" at the position corresponding to 2.
• For "Pop" (7 students): Place 7 dots above "Pop" at the position corresponding to 7.
• For "R&B" (3 students): Place 3 dots above "R&B" at the position corresponding to 3.
• For "Rock" (8 students): Place 8 dots above "Rock" at the position corresponding to 8.

Final Visuals (Description)

• Horizontal Bar Graph: Each genre has a horizontal bar whose length is proportional to the number of students (e.g., "Rock" has the longest bar, "Classical" the shortest).
• Dot Plot: Each genre has a row of dots, with the number of dots equal to the number of students (e.g., "Rock" has 8 dots, "Classical" has 1 dot).

(Note: Since the actual drawing is a graphical task, the above steps describe how to construct the graphs based on the given data. If you were to draw them on paper or using software, you would follow these steps to represent the data accurately.)

Answer:

To create the horizontal bar graph and dot plot for the students' music preferences data:

Horizontal Bar Graph (Left)

1. Axes Setup: The vertical axis lists the music genres (Classical, Country, Hip Hop, Jazz, Pop, R&B, Rock) in order from bottom to top (or top to bottom as per the given layout). The horizontal axis is a number line from 0 to 10, representing the number of students.
2. Drawing Bars:

• For "Classical" with 1 student: Draw a horizontal bar starting from the "Classical" label on the vertical axis, extending to 1 on the horizontal axis.
• For "Country" with 2 students: Draw a bar extending to 2.
• For "Hip Hop" with 5 students: Draw a bar extending to 5.
• For "Jazz" with 2 students: Draw a bar extending to 2.
• For "Pop" with 7 students: Draw a bar extending to 7.
• For "R&B" with 3 students: Draw a bar extending to 3.
• For "Rock" with 8 students: Draw a bar extending to 8.

Dot Plot (Right)

1. Axes Setup: The vertical axis lists the music genres (same order as the bar graph). The horizontal axis is a number line from 0 to 10, representing the number of students.
2. Plotting Dots:

• For "Classical" (1 student): Place 1 dot above the "Classical" label at the position corresponding to 1 on the horizontal axis.
• For "Country" (2 students): Place 2 dots above "Country" at the position corresponding to 2.
• For "Hip Hop" (5 students): Place 5 dots above "Hip Hop" at the position corresponding to 5.
• For "Jazz" (2 students): Place 2 dots above "Jazz" at the position corresponding to 2.
• For "Pop" (7 students): Place 7 dots above "Pop" at the position corresponding to 7.
• For "R&B" (3 students): Place 3 dots above "R&B" at the position corresponding to 3.
• For "Rock" (8 students): Place 8 dots above "Rock" at the position corresponding to 8.

Final Visuals (Description)

• Horizontal Bar Graph: Each genre has a horizontal bar whose length is proportional to the number of students (e.g., "Rock" has the longest bar, "Classical" the shortest).
• Dot Plot: Each genre has a row of dots, with the number of dots equal to the number of students (e.g., "Rock" has 8 dots, "Classical" has 1 dot).

(Note: Since the actual drawing is a graphical task, the above steps describe how to construct the graphs based on the given data. If you were to draw them on paper or using software, you would follow these steps to represent the data accurately.)