Describing Data with Graphs Chapter 1

(Page 8) 1.1 Variables and Data Variable – a characteristics that changes or varies over time and for different individuals or objects under consideration. Experimental unit – the individual or object on which a variable is measured. Population – is the set of all measurements of interest to the investigator. Sample – is a subset of measurements selected from the population of interest.

(Page 8 – 9) Take up Example 1.1 and Figure 1.1 Univariate data result when a single variable is measured on a single experimental unit. Bivariate data result when two variables are measured on a single experimental unit. Multivariate data result when more than two variables are measured.

(Page 10) 1.2 Types of Variables Qualitative Variables – measure a quality or characteristics on each experimental unit. Example: Political Affiliation: Republican, Democrat, Independent Taste Ranking: Excellent, good, fair, poor Color of M&M’s candy: red, yellow, orange green Brand of shoes: Adidas, Fila, Nike Relationships: husband, wife, nephew, niece, sister, brother

(Page 10) Quantitative Variables – measure a numerical quantity or amount on each experimental unit. Example: Prime Interest Rate: 10%, 5%, 15%, 20% Number of Passengers on a flight Weight of a package ready to be shift Volume of orange juice in a glass Stat 101 Major Exam marks Number of students in a class

(Page 10) Discrete Variable can assume only a finite or countable number of values. Example: Number of family members Number of new car sales Number of defective tires Number of shoes Number of cell phones Continuous Variable – can assume the infinitely many values.

(Page 10) Take up Example 1.2 Qualitative, Quantitative, Discrete or Continuous The most frequent use of your microwave oven: reheating, defrosting, warming The number of consumers who refuse to answer a telephone survey The door chosen by a mouse in a maze experiment: A, B, C The winning time for a horse running in the Kentucky Derby The number of children in a fifth-grade class who are reading at or above grade level

(Page 14 – 15) Exercises: 1.1, 1.2, 1.3 1.1 a. student 1.3 a. discrete b. exam b. continuous c. patient c. continuous d. plant d. discrete e. car 1.2 a. Quantitative b. Quantitative c. Qualitative d. Qualitative