1. Intro to Statistics and Data
Chapter 1
Chapter 2

2. What is Statistics?
Statistics is the science of learning from data, and of measuring, controlling, and communicating uncertainty
In a word: variation

3. Think, Show, Tell Think first. Know where you are headed and why.
Show your work. The mechanics of the calculation are important but can not exist on there own.
Tell your conclusion in the context of the problem

4. What are these? 16 37 46 25 33 45 24 42 19 40 5 26 34 28 49 73

5. Barry Bonds HRs by year
1986 16
1994 37
2002 46
1987 25
1995 33
2003 45
1988 24
1996 42
2004
1989 19
1997 40
2005 5
1990
1998
2006 26
1991
1999 34
2007 28
1992
2000 49
1993
2001 73

6. Data Information in context Context: Who What (and in what units)
Why (if possible)
Where
When
How
By Whom

7. The W’s
Who?-- The cases (or individuals) about which (or whom) we gather information
MLB Seasons from 1986 to 2007
What? – Variables are characteristics recorded about each case
Barry Bonds’ HRs (HRs)
Why? – The reasons for gathering the data can influence our analysis, can help determine which type of variable

8. The W’s cont.
When and where? – Help provide additional context for the data
How? – The methodology for gathering the data can determine whether you have useful information or pure crap

9. More about What Variables come in two types
A categorical (or qualitative) variable names categories and answers questions about how cases fall into those categories. (e.g., sex, race, ethnicity)
A quantitative variable is a measured variable (with units) that answers questions about the quantity of what is being measured. (e.g. income ($), height (inches), weight (pounds))
!!!Always include units!!!

10. What can go wrong?
Don’t label a variable as categorical or quantitative without thinking about the question you want it to answer.
Just because your variable’s values are numbers, don’t assume that it’s quantitative.
Always be skeptical—don’t take data for granted.