Example 4

EXAMPLE 4 Constructing a pie chart

Construct a pie chart for the app type data from Example 2.

Solution

The relative frequencies from Example 2 are shown in Table 5. We multiply each relative frequency by 360° to get the number of degrees for that section (slice) of the pie chart.

Page 45

Table 2.5: Table 5 Finding the number of degrees for each slice of the pie chart

Variable: app type	Relative frequency	Multiply by 360°	Degrees for that section
Games	$7 / 20 = 0.35$	$0.35 \times 360 °=$	$126 °$
Social networking	$5 / 20 = 0.25$	$0.25 \times 360 °=$	$90 °$
Music	$3 / 20 = 0.15$	$0.15 \times 360 °=$	$54 °$
Photo and video	$3 / 20 = 0.15$	$0.15 \times 360 °=$	$54 °$
Sports	$2 / 20 = 0.10$	$0.10 \times 360 °=$	$36 °$
Total	$20 / 20 = 1.00$		$360 °$

Our pie chart will have five slices—one for each app type category. Use the compass to draw a circle. Then, use the protractor to construct the appropriate angles for each section. From the center of the circle, draw a line to the top of the circle. Measure your first angle using this line. For the Games app type, we need an angle of 126°. This angle is shown in Figure 3. Then, from there, measure your second angle—in this case, the 90° right angle for Social networking apps. Continue until your circle is complete.

FIGURE 3 Pie chart of app type data.

NOW YOU CAN DO

Exercises 19, 20, 35, and 36.