1 m02-data collection/types department of ism, university of alabama, 1995-2003 lesson objectives -...
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1M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Lesson Objectives - M02
Understand “Scales of Measurement.”
Understand “Quantitative Variables”and the two types.
Understand “Categorical Variables”and the three types.
Determine which of the above to useto make a decision.
2M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
STATISTICS is the science of
collecting,collecting, organizing, organizing, summarizing, summarizing, andand interpreting… interpreting…
DATA
for the purpose of _______________.
3M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Problem Situation
Your first job as a newly named marketing associate for Taco Casa:
Manage a task force to determine the location of a new store from among four candidate cities.
What do you do?
4M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Must make a decision!
Where do you start?
5M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Back to Taco Casa Problem:
Your task force is charged with comparing characteristics of households in the four different cities (market profiles).
6M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Variables that may be usefulfor site selection.
7M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Variables that may be usefulfor site selection.
8M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Variables that may be usefulfor site selection.
9M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
What to measure?
How to measure?
Best data gathering approach?
Designing a data collection is not simple!
10M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Drawing conclusions about
the population (___________),
based on a sample
(___________).
Statistical Inference
11M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Definition: Variable
Any measurable characteristic of a person or thing.
In a data set, always observe the:
i) number of variables
ii) types of variables.
In a data set, always observe the:
i) number of variables
ii) types of variables.
12M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Rule of Thumb:
If averages or differences have meaning, a variable is ________________.
Ex:
13M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Types of Quantitative Variables
Discrete: _____________ values with gaps between them. Note: Not necessarily integers. May be an infinite number of values.
Continuous: ___________ in an interval can occur.
14M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Scales of Measurement
Nominal
Ordinal
Interval
Ratio
Each value is a __________
________ has meaning
Units of measurement
True absolute zero
15M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Rule of Thumb:
A variable that classifies people or things, is _________ or ______________.
Ex: sex, political affiliation, race, country of origin.
16M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Types of Qualitative Variables
Nominal: Numbers are used to “NAME” categories.____________: The categories have a natural ordering.Binary: Two categories (usually assigned values of “0” or “1”).
17M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Identify the type:
Height:
Stock Quote:
Age:
Course Grade:
Football jersey number:
18M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Identify the type:
Answer to aT/F Question:
Number ofcorrect T/Fanswers in 5 questions:
Proportion ofcorrect T/Fanswers in 5 questions:
19M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Handout: Data for 100 Households (FAM100.DAT)
Income1 Annual income of principal wage earner
Income2 Annual income of secondary wage earner
FamSize Family size
Own? Own or rent (1 = own, 0 = rent)
TotalDebt Total indebtedness (excluding mortgage)
Housing Monthly house payment or rent
Utility Average monthly utility expenditure
City City of residence (1, 2, 3, 4)
20M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
After we collect data, then what?
Organize / Summarize Data
Graphical Numerical
21M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
22M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Descriptive Statistics:
numerical summaries and/or graphical display of (sample) data.
Inferential Statistics:
Using sample data to make conclusions about the population from which the sample was taken.
23M02-Data Collection/TypesM02-Data Collection/Types Department of ISM, University of Alabama, 1995-2003
Population:
collection of all items of interest in a study
Sample: subset selected to be representative of the population