2
T.1 TABULAR REPRESENTATION OF DATA:
QUALITATIVE DATA
As mentioned in chapter 1, qualitative data is data where each entity is
assigned (placed into) one of a limited number of possible categories, such
as male/female, white/black/Hispanic, or brand-of-car-you-drive.
The best we can do with such data is to COUNT how many entities in the
data set fall into each of the possible categories (the data
frequency
for
that category), then calculate what FRACTION or PERCENTAGE of the total
belongs in each category (
relative frequency
).
FREQUENCY DISTRIBUTION
Let us use as an example the grades given out in a section of BUS-271 in
the past. Each entity (that is, each student) was assigned one out of a small
number of possible grades: A,B,C,D,F,W.
Say that students in the particular class were assigned the following grades:
A, B, C, D, F, W, A, B, C, F, W, A, B, C,F, W, A, C, W, A, W, A, W, A, A, A
Let us first rearrange the observations so as to group similar grades
together. (Since these data are ordinal, there is a natural order in which to
list or sort them.)
A, A, A, A, A, A, A, A, A, B, B, B, C, C, C, C, D, F, F, F, W, W, W, W, W, W
From this, we can make a list of the possible data values (categories)
represented in the data set: A, B, C, D, F, W.
If we now count how many students received each grade, we have:
A
9
B
3
C
4
D
1
F
3
W
6
---
26
Total number of observations: n = 26