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Research
Methods STA630
VU
Lesson
31
DATA
PRESENTATION
Tables
and graphs (pictorial presentation of
data) may simplify and
clarify the research data.
Tabular
and
graphic representation of data may
take a number of forms, ranging from
computer printouts to
elaborate
pictographs. The purpose of
each table or graph,
however, is to facilitate the
summarization
and
communication of the meaning of the
data.
Although
there are a number of standardized forms
for presenting data in table or
graphs, the creative
researcher
can increase the effectiveness of
particular presentation. Bar
charts, pie charts,
curve
diagrams,
pictograms, and other graphic forms of
presentation create a strong visual
impression.
The
proliferation of computer technology in
business and universities has
greatly facilitated
tabulation
and
statistical analysis. Commercial packages
eliminate the need to write a
new program every
time
you
want to tabulate and analyze data
with a computer. SAS,
Statistical Package for the
Social Sciences
(SPSS),
SYSTAT, Epi. Info. And
MINITAB is commonly used statistical
packages. These
user
friendly
packages emphasize statistical
calculations and hypothesis testing for
varied types of data. They
also
provide programs for
entering and editing data. Most of
these packages contain
sizeable arrays of
programs
for descriptive analysis and
univariate, bivariate, and
multivariate statistical analysis.
Results
with one variable
Frequency
Distribution
Several
useful techniques for displaying
data are in use. The
easiest way to describe the
numerical data
of
one variable is with a frequency
distribution. It can be used
with nominal-, ordinal-,
interval-, or
ratio-level
data and takes many forms.
For example we have data of
400 students. We can
summarize
the
data on the gender of the students at a glance
with raw count or a
frequency
distribution
Table
1: Frequency distribution of
students
Gender
Frequency
Percent
Male
300
75
Female
100
25
Total
400
100
We
can present the same
information in a graphic form.
Some common types of graphic
presentations
are
the histograms,
bar chart, and pie
chart. Bar
charts or graphs are used
for discrete variables.
They
can
have vertical or horizontal orientation
with small space between the
bars. The terminology is
not
exact,
but histograms are usually
upright bar graphs for
interval or ratio data.
Presentation
of data in these forms lays
emphasis on visual representation and
graphical techniques over
summary
statistics. Summary statistics may
obscure, conceal, or even misrepresent the
underlying
structure
of the data. Therefore it is suggested
that data analysis should
begin with visual
inspection.
The
presented data has to be
interpreted. The purpose of
interpretation is to explain the meanings
of the
data
so that we can make inferences and
formulate conclusions. Therefore,
interpretation
refers
to
making
inferences pertinent to the meaning and
implications of the research
investigation and drawing
conclusions.
In order for interpretation, the
data have to be meaningfully analyzed.
For purposes of
analysis
the researchers use
statistics.
104
Research
Methods STA630
VU
The
word statistics
has
several meanings. It can mean a set of
collected numbers (e.g. numbers
telling
how
many people living in a
city) as well as a branch of applied
mathematics used to manipulate
and
summarize
the features of numbers. Social
researchers use both types of statistics.
Here, we focus on
the
second type ways to manipulate and
summarize numbers that
represent data from research
project.
Descriptive
statistics describe
numerical data. They can be categorized
by the number of variables
involved:
univariate, bivariate, or multivariate
(for one, two, and three or more
variables). Univariate
statistics
describe one
variable.
Researchers
often want to summarize the
information about one
variable into a single
number. They
use
three measures of central tendency, or
measures of the center of the frequency
distribution: mean,
median
and mode, which are
often called averages (a
less precise and less clear
way to say the same
thing).
The mode
is
simply the most common or frequently
occurring number. The
median
is
the
middle
point. The mean
also
called the arithmetic average, is the
most widely used measure of
central
tendency.
A particular central tendency is used
depending upon the nature of the
data.
Bivariate
Tables
The
bivariate contingency table is
widely used. The table
is based on cross-tabulation
(cross-
classification);
that is the cases are
organized in the table on the basis of
two variables at the same
time.
A
contingency table is formed by
cross-tabulating the two or more variables. It is
contingent because
the
cases in each category of a
variable get distributed into
each category of a second
variable. The
table
distributes cases into
categories of multiple variables at the
same time and shows
how the cases, by
the
category of one variable, are
"contingent upon" the categories of the
other variables.
Constructing
Percentage Tables
It
is to construct a percentage table, but
there are ways to make it look
professional. Let us take
two
variables
like the age of the respondents and
their attitude towards "women
empowerment." Assuming
that
age affects the attitude towards women
empowerment let us hypothesize: the lower
the age, the
higher
the favorable attitude towards "women
empowerment." The age range of the
respondents is 25 to
70,
and the attitude index has three
categories of "highly favorable,"
"medium favorable," and
"low
favorable."
The age variable has so
many categories that making
a table with that number
becomes
unwieldy
and meaningless. Therefore, we regroup
(recode) the age categories into three
i.e. under 40
years,
40 60 years, and 61 +
years.
Univariate
table for age
·
Table 2:
Age of the respondents
.
·
Age
(Yrs.)
Frequency
Percent
.
·
Under
40
1000
33.3
·
40
60
1000
33.3
·
61
+
1000
33.3
.
·
Total
3000
100
.
105
Research
Methods STA630
VU
Univariate
table for attitude
·
Table 3:
Attitude towards women
.
empowerment
.
Attitude
Frequency
Percent
Hi
Favorable
1100
37
Med
Favorable
1050
35
Lo
Favorable
850
28
Total
3000
100
Bivariate
table
·
Table 4: Age by attitude towards women
.
empowerment
.
Age
(in years)
.
Level
of
under
40
40
60
61
+
Total
attitude
F.
%
F.
%
F
%
F
%
Hi
Favorable
600
60
300
30
200
20
1100
37
Med.
Favorable 300
30
500
50
250
25
1050
35
Lo
Favorable
100
10
200
20
500
50
850
28
Total
1000
100
1000
100
1000
100
3000
100
106
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