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© 2014 Pacific Crest
299
Scenario 3:
Nominal Data
A cosmetologist is interested in the hair color of women in a certain ethnic
community. She designs the following coding scheme.
Level 1: Black
Level 2: Darkest Brown
Level 3: Very Dark Brown
Level 4: Dark Brown
Level 5: Brown
Level 6: Light Brown
Level 7: Dark Blonde
Level 8: Medium Blonde
Level 9: Blonde
Step
Watch it Work!
1.
Describe the data
set
A trained cosmetologist is able to categorize each woman. Her results follow:
5 5 4 2 3 1 9 5 4 7 8 2 3 4 4 3 5 3 2 6 9 5
2.
Describe the type
of data
The differences and the ratios are irrelevant. Since this data is used to establish
categories, it is nominal data.
3.
Construct a
histogram or bar
graph
Use technology to
construct a bar graph.
0
1
2
3
4
5
6
1 2 3 4 5 6 7 8 9
4.
Determine which
measures of CT
are reasonable
Since the data set is nominal, the only reasonable measure of central tendency
is the mode.
5.
Compute the
measures of CT
and determine
which is best
The mode is the most occurring response. In this example, category 5 is the
mode. The most common hair color was brown.
6.
Validate
Repeat the process with a second set of women and see if the results are
similar.
7.1 Central Tendency