1. Intro to Statistics
Chapter 2: Data

2. What is data? da·ta noun 1. a plural of datum.
2. ( used with a plural verb ) individual facts, statistics, or items of information: These data represent the results of our analyses. Data are entered by terminal for immediate processing by the computer.
3. ( used with a singular verb ) a body of facts; information: Additional data is available from the president of the firm.
From dictionary.com:

3. Information Age, data all around us
What types of data do you encounter?

4. Data Sports results/statistics Store inventory/sales records
Class schedule and grades
Medical measurements/test results
Personal information
Resume/Job history

5. Who and What of Data Each row in the table represents one set of data
Each column represents the individual characteristics being recorded or measured
What
Student ID
Semester
Year
# credits
GPA
Fall
2010 12
3.1
Spring 9
2.6
Summer I
2011 3
4.0
Who

6. Data: Categorical vs. Quantitative
Data can generally be classified as one of these 2 types
Quantitative: measurement, with units
Categorical: labels, categories
Numbers don’t always mean data is quantitative!

7. Quantitative Data Measurements: Scores: Statistics Age Dollar Amounts:
Heights, weights, distances, times, rates, …
Scores:
Tests, ratings, competitions, …
Statistics
Sports, specifications, …
Age
Dollar Amounts:
Incomes, sales, prices, …

8. Categorical Data Any values that are words are generally categorical
Categorical Data involving numbers:

9. Categorical Data Any values that are words are generally categorical
Categorical Data involving numbers:
Phone numbers
Zip Codes
Student ID numbers
Think about whether or not there are units
Do the values have numeric significance?