1. Describing Data with Graphs
Chapter 1

2. (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.

3. (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.

4. (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

5. (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

6. (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.

7. (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

8. (Page 14 – 15)
Exercises: 1.1, 1.2, 1.3
1.1 a. student 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