1. AP Statistics
Variables

2. Vocabulary Statistics – The science of data.
Individuals – The objects described by a set of data. Can be people, animals or things.
Population – Set of all possible individuals.
Variable – Any characteristic of an individual.

3. Exploratory Data Analysis (Descriptive Statistics)
Basic Strategies:
1. Examine each variable by itself, then move on to study relationships between variables.
2. Graph and summarize specific aspects of the data.

4. More Vocabulary
Univariate Data – Describes a single aspect of Data (age).
Bivariate/Multivariate Data – Describes more than one aspect (gender and age).

5. Types of Variables
Categorical Variable – Describes a category or group an individual belongs to. *Groups can’t be rank-ordered.
Examples – Gender, eye color, age groupings.

6. Types of Variables
Quantitative Variables – Uses numerical values to describe the variable. One can rank order and can perform arithmetic operations on quantitative data.
Can be further broken down into Discrete and Continuous quantitative variables.

7. Quantitative Variables
Discrete - Isolated points on a number line (ages, grades).
These are items which can be counted.
Continuous – Can exist in an interval on a number line (GPA’s, task completion times)
These are item which must be measured.

8. Distribution of a Variable
What values a variable takes and how often it takes them.

9. Qualitative Graphs
Bar Graphs

10. Qualitative Graphs Continued
Circle Graphs:

11. Homework
Worksheet - Categorical vs. Quantitative Variables