Section 1.2 Types of Data 13 Check Your Understanding 1. A pollster asks a group of six voters about their political affiliation (Republican, Democrat, or Independent), their age, and whether they voted in the last election. The results are shown in the following table. Political Voted in Voter Affiliation Age Last Election? 1 Republican 34 Yes 2 Democrat 56 Yes 3 Democrat 21 No 4 Independent 28 Yes 5 Republican 61 No 6 Independent 46 Yes a. How many individuals are there? b. Identify the variables. c. What are the data for individual #3? Answers are on page 18. Objective 2 Distinguish between qualitative and quantitative variables Qualitative and Quantitative Variables Variables can be divided into two types: qualitative and quantitative. Qualitative variables, also called categorical variables, classify individuals into categories. For example, college major and gender are qualitative variables. Quantitative variables are numerical and tell how much or how many of something there is. Height and score on an exam are examples of quantitative variables. SUMMARY • Qualitative variables classify individuals into categories. • Quantitative variables tell how much or how many of something there is. Explain It Again Another way to distinguish qualitative from quantitative variables: Quantitative variables are counts or measurements, whereas qualitative variables are descriptions. EXAMPLE 1.11 Distinguishing between qualitative and quantitative variables Which of the following variables are qualitative and which are quantitative? a. A person’s age b. A person’s gender c. The mileage (in miles per gallon) of a car d. The color of a car Solution a. Age is quantitative. It tells how much time has elapsed since the person was born. b. Gender is qualitative. It consists of the categories “male” and “female.” c. Mileage is quantitative. It tells how many miles a car will go on a gallon of gasoline. d. Color is qualitative. Objective 3 Distinguish between ordinal and nominal variables Ordinal and Nominal Variables Qualitative variables come in two types: ordinal variables and nominal variables. An ordinal variable is one whose categories have a natural ordering. The letter grade received in a class, such as A, B, C, D, or F, is an ordinal variable. A nominal variable is one whose
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