1. Elementary Statistics Picturing the World
Data Classification

2. 1.2 Data Types and Levels of Measurements
Qualitative data – consist of values that describe qualities or non-numerical (i.e. brand names, letter grades)
Quantitative data – consist of values representing counts or measurements (i.e. social security numbers, percentage grades)

3. 1.2 Data Types and Levels of Measurements
Four Levels of Measurement:
Nominal – data consisting of names, labels, or categories only. The data are qualitative and can not be ranked or ordered
Ordinal – qualitative or quantitative data that can be arranged in some order. It generally does not make sense to do computations with ordinal data.
Interval – quantitative data which intervals are meaningful, but ratios are not. Data at this level have an arbitrary zero point.
Ratio – quantitative data which both intervals and ratios are meaningful. Data at this level have a true zero point.

4. 1.2 Data Types and Levels of Measurements
Four Levels of Measurement:
Nominal – Flavors (vanilla comes before chocolate), gender, type of car you drive, occupation
Ordinal – Movie ratings ( 3 stars vs. 2 stars)
Interval – temperature (55 degrees is more than 11 degrees, but 55 degrees is not necessarily 5 times hotter than 11 degrees because 0 does not represent no temperature i.e. oven bake times), SAT scores
Ratio – distances (10 miles is twice 5 miles, and 0 miles means no distance), salary, age

5. 1.2 Data Types and Levels of Measurements

6. 1.2 Data Types and Levels of Measurements
Eye color on a dating survey?
Qualitative
Quantitative

7. 1.2 Data Types and Levels of Measurements
Scores on a multiple choice exam?
Qualitative
Quantitative

8. 1.2 Data Types and Levels of Measurements
Flavors of ice cream?
Qualitative
Quantitative

9. 1.2 Data Types and Levels of Measurements
College majors?
Qualitative
Quantitative

10. 1.2 Data Types and Levels of Measurements
Weights of trucks?
Qualitative
Quantitative

11. 1.2 Data Types and Levels of Measurements
Incomes of college graduates?
Qualitative
Quantitative

12. 1.2 Data Types and Levels of Measurements
Student rankings of cafeteria food: excellent, good, fair, poor?
Nominal
Ordinal
Interval
Ratio
definite order

13. 1.2 Data Types and Levels of Measurements
Weights of wrestlers?
Nominal
Ordinal
Interval
Ratio
true zero point

14. 1.2 Data Types and Levels of Measurements
Calendar years of historic events, such as 1776, 1945, 2001?
Nominal
Ordinal
Interval
Ratio
because dates have no meaningful ratios and zero does not represent beginning of time

15. 1.2 Data Types and Levels of Measurements
Numbers on uniforms?
Nominal
Ordinal
Interval
Ratio
no ordering

16. 1.2 Data Types and Levels of Measurements
Temperatures on the Celsius scale?
Nominal
Ordinal
Interval
Ratio
because temperature has no meaningful ratios and zero degrees does not mean “no heat”

17. 1.2 Data Types and Levels of Measurements
Runner’s times in the Boston Marathon?
Nominal
Ordinal
Interval
Ratio
true zero point