12.2 Frequency Distributions and Statistical Graphs 779 their responses. Since the total circle represents 100%, the sum of the sectors should be 100%, and it is. Exercises Warm Up Exercises In Exercises 1–8, fill in the blank with an appropriate word, phrase, or symbol(s). 1. A listing of observed values and the corresponding frequency of occurrence of each value is called a(n) ____________ distribution. Frequency 2. In a frequency distribution, the class with the greatest frequency is called the ____________ class. Modal 3. In a frequency distribution, another name for the midpoint of a class is the class ____________. Mark 4. A bar graph with observed values on its horizontal scale and frequencies on its vertical scale is called a(n) ____________. Histogram 5. A line graph with observed values on its horizontal scale and frequencies on its vertical scale is called a frequency ____________. Polygon SECTION 12.2 Figure 12.11 Credit cards 32% Other 1% Electronic 9% Check 9% Debit cards 49% Paying for Purchases Source: Forbes.com In the next example, we will discuss a circle graph. Favorite Performance at the Circus Other 5% Jugglers 14% Acrobats 17% Trapeze Acts 38% Clowns 26% Figure 12.12 Example 9 Circus Performances Eight hundred people who attended a circus were asked to indicate their favorite performance. The circle graph in Fig. 12.12 shows the percentage of respondents that answered trapeze acts, clowns, acrobats, jugglers, and other. Determine the number of respondents for each category. Solution To determine the number of respondents in a category, we multiply the percentage for each category, written as a decimal number, by the total number of people, 800. Table 12.4 indicates the results. Table 12.4 Performance Percent of Respondents Percent Written as a Decimal Number Number of People Trapeze Acts 38% 0.38 0.38 800 304 × = Clowns 26% 0.26 0.26 800 208 × = Acrobats 17% 0.17 0.17 800 136 × = Jugglers 14% 0.14 0.14 800 112 × = Other 5% 0.05 0.05800 40 × = Total 800 As we can see from the table, 304 people indicated that the trapeze acts were their favorite performance, 208 indicated clowns, 136 people indicated the acrobats, 112 people indicated the jugglers, and 40 people indicated some other performance. 7 Now try Exercise 41 Instructor Resources for Section 12.2 in MyLab Math • Objective-Level Videos 12.2 • PowerPoint Lecture Slides 12.2 • MyLab Exercises and Assignments 12.2
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