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Unit 1: Introduction to Univariate & Bivariate Analysis using SPSS
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The three parts of SPSS: the data manager, data files, and output files
Loading data files, changing data sets, using the utilities function to examine variable values
Univariate analysis
o Frequencies
o Valid Percent
o Cumulative Percent
Examining a bivariate relationship between dichotomous variables
o Crosstabulations
 Reading 2 x 2 tables
 Data loss
 Cells
 Column, row, and total percentages
o Statistics
 Pearson Chi Square
 Cramer’s V
Reference information
Pearson Chi Square
p. = probability that results occurred by chance
<value= <likely by chance
.05 or less = accepted as significant (not chance occurrence)
Cramer’s V
0- 1.00 = strength of association
<.10 = weak
.10-.30 = moderate
>.30 = strong
Sample Table: Crosstabulation of support for capital punishment by sex ,
with column percentages reported.
Respondent’s Sex
total
male
female
82.6%
71.6%
76.6%
Capital
favor
Punishment
17.4%
28.4%
23.4%
oppose
total
100.0%
100.0%
100.0%
Pearson X2:p.<.000; Cramer’s V=.129
Source: 1996 GSS Tab subset
Sample results statement for bivariate crosstabulation of nominal level dichotomous variables:
While a majority (76.6%) of respondents in the 1996 GSS sample support capital punishment (DPS), there is a
moderately strong (V= .129), statistically significant difference (p.<.000) in DPS by sex, with 82.6% of men
favoring capital punishment, in contrast to 71.6% of women.
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Univariate Analysis: Examining a single variable
Ex. 1) Fill in the frequencies and valid percents for the following variables.
Data set
Variable
Attributes
GSS96TAB
CAPPUN
Favor
1
Oppose
2
Liberal
1
Moderate
2
conservative
3
Extremely liberal
1
Liberal
2
Slightly liberal
3
Moderate
4
Slightly conservative
5
Conservative
6
Very conservative
7
Favor
1
Oppose
2
GSS96TAB
GSS96COR
GSS72SAV
POLVIEWS
POLVIEWS
CAPPUN2
Values
GSS96TAB
DEGREE
At least some college
2
GSS72.SSAV
DEGREE
At least some college
2
GSS96COR
Percent of respondents who identify themselves
as liberal to some degree?
Frequency
Valid
%
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Bivariate Analysis: Examining the relationship between two variables.
Ex. 2) Does support for capital punishment vary by sex in the 1996 GSS subset?
o
o
o
o
o
Analyze----Descriptives----Crosstabs
Row: Dependent variable (D.V.) (Cappun)
Column: Independent variable (I.V.) (Sex)
Cells: Column & total
Statistics: Chi Square (X2) & Phi/Cramer’s V
Is the difference statistically significant?
(low chance of being random)
USE: Pearson Chi Square:
p. = probability that results occurred by
chance
<value= <likely by chance
.05 or less = accepted as significant
If it is significant, how strong is the association?
USE: Cramer’s V
0- 1.00 = strength of association
<.10 = weak
.10-.30 = moderate
>.30 = strong
Fill in the following table and sentences with information from the SPSS crosstabulation of SEX & CAPPUN in the
GSS96TAB data set. If the answer to a question is not included in the chart, write: N/A. (Indicate N/A even if you
could calculate the answer, but it is not directly observable).
Table 1: Crosstabulation of support for capital punishment by sex ,
with column percentages reported.
Respondent’s Sex
total
male
female
favor
Capital
Punishment
oppose
total
; Cramer’s V=
Pearson X2: p
Source: 1996 GSS Tab subset
The total number of respondents (n) with data used in the crosstabulation = ________
The number of females who oppose the death penalty = __________
The percent of males who favor the death penalty = ____________
The percent of those favoring the death penalty who are female = __________
The total number of females responding to the death penalty question = __________
The percent of respondents opposing the death penalty = _____________
The percent of those opposing the death penalty who are male= ______________
Are the sex differences in support for capital punishment statistically significant? _________
If so, how strong are the sex differences? _____________
(SEE COVER PAGE FOR A WRITTEN DESCRIPTION OF THE DATA IN THIS TABLE)
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Ex. 3) Practice Question: Do men and women differ in fear in the 1996 GSS subset?
(GSS FEAR question = Is there any area right around here-that is, within a mile-where you would be afraid to walk
alone at night? Yes- 1 No-2
Table 1: Crosstabulation of support for capital punishment by sex ,
with column percentages reported.
Respondent’s Sex
male
female
total
yes
Fear
no
total
Pearson X2: p
; Cramer’s V=
Source: 1996 GSS Tab subset
The total number of respondents (n) with data used in the crosstabulation = ________
The number of females who are afraid to walk alone at night = __________
The percent of males who are not afraid to walk alone at night = ____________
The percent of those who are afraid to walk alone at night who are female = __________
The total number of females responding to the fear question = __________
The percent of respondents who are afraid to walk alone at night = _____________
The percent of those who are not afraid who are male= ______________
Are the sex differences in fear statistically significant? _________
If so, how strong are the sex differences? _____________
While a majority (
) of respondents in the 1996 GSS sample say that they are/ are not afraid to walk alone
at night, there is a _____________ (V.
), statistically significant difference (p.
with _________of men expressing fear, in contrast to __________of women.
) in fear by sex,
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Unit 1: Lab Review exercise: Bivariate analysis of nominal level dichotomous variables.
Fill in the following chart. Enter N/A under Cramer’s V if P is not significant.
Sample Table: Crosstabulation of support for capital punishment by sex ,
with column percentages reported.
Respondent’s Sex
total
male
female
82.6%
71.6%
76.6%
Capital
favor
Punishment
17.4%
28.4%
23.4%
oppose
total
100.0%
100.0%
100.0%
Pearson X2:p.<.000; Cramer’s V=.129
Source: 1996 GSS Tab subset
DATA SET
DEP.VAR.
IND.
VAR.
GSS96TAB
EXAMPLE
CAPPUN
SEX
GSS96TAB
SPANKING
RACE
GSS96TAB
TRUST
SEX
GSS96TAB
GUNLAW
CAPPUN
GSS96TAB
FEWORK
SEX
GSS96TAB
VOTE92
RACE
GSS72SAV
FEWORK
SEX
GSS72SAV
VOTE68
RACE
GSS72SAV
CAPPUN
SEX
CHI
SQ
P
P<.000
SIG?
YES/
NO
yes
CRAMER’S
V
.129
STRENGTH
I.V/DV
ATT1%
moderate
Male
82.6%
favor
I.V/DV
ATT2
%
Female
71.6%
favor
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Answer the following questions referring to lab review exercise above and using the results reporting
paragraph demonstrated in this packet.
Q.1) Are race differences in support for spanking evident in the 1996 GSS data set?
Q.2) How have racial differences in voting changed from the 1972 GSS sample to the 1996 GSS sample and how
might you explain this sociologically?
Q.3) How have sex differences in attitudes toward women working changed from the 1972 GSS sample to the 1996
GSS sample and how might you explain this sociologically?