1. AP Statistics
Day 1:
Objective: Students will be able to distinguish between categorical and quantitative variables.
WELCOME BACK TO OMHS!

2. We study statistics because…
… anecdotal evidence is not reliable.
… we don’t wish to be lied to.
… spotting trends helps us make good decisions
Simply, we study statistics because we want to make sense of the world.

3. Introduction to Statistics
Statistics is the science of data.
Any set of data contains information about some group of individuals.
The information is gathered in variables.
A variable is any characteristic of an individual.
Individuals are the objects described by a set of data. (People, animals, things, etc.)

4. Understanding and Examining Data
Questions to ask yourself:
What individuals do the data describe?
How many individuals appear in the data?
How many variables are there?
What are the definitions of each variable

5. Questions to ask yourself: (cont.)
5) In what units are each variable recorded in?
Is there any reason to mistrust the data?
Why was the data gathered?
What questions do we want to answer?
Do we want to draw conclusions about individuals other than the ones we actually have data for?

6. Types of Variables
Categorical Variables: record which of several groups or categories an individual belongs to.
Quantitative Variables: take numerical values for which it makes sense to do arithmetic operations like adding and averaging.

7. Distribution
“The distribution of a variable tells us what values the variable takes and how often it takes these values.”
How distributions differ between categorical and quantitative variables?

8. Types of Graphical Displays

10. Class Work
Exercises 1.1 – pages 8 – 9 (textbook)

11. Homework
Read from page 5 (start at Example 1.1) through page 8 (end at Exercises)
Do exercise 1.14 on page 25