Unit 1: Introduction to Univariate & Bivariate Analysis Using SPSS

Unit 1: Introduction to Univariate & Bivariate Analysis using SPSS

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
Frequencies
Valid Percent
Cumulative Percent
Examining a bivariate relationship between dichotomous variables
Crosstabulations
Reading 2 x 2 tables
Data loss
Cells
Column, row, and total percentages
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
male / female / total
Capital
Punishment / favor / 82.6% / 71.6% / 76.6%
oppose / 17.4% / 28.4% / 23.4%
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.

NON-SIGNIFICANT RESULTS: While a majority (77.6%) of respondents in the 1996 GSS sample support capital punishment (DPS), there is no statistically significant difference (p.057) in support by attitudes toward law enforcement spending.

Univariate Analysis: Examining a single variable

Ex. 1) Fill in the frequencies and valid percents for the following variables.

Data set / Variable / Attributes / Values / Frequency / Valid %
GSS96TAB / CAPPUN / Favor / 1
Oppose / 2
GSS96TAB / POLVIEWS / Liberal / 1
Moderate / 2
conservative / 3
GSS96COR / POLVIEWS / Extremely liberal / 1
Liberal / 2
Slightly liberal / 3
Moderate / 4
Slightly conservative / 5
Conservative / 6
Very conservative / 7
GSS72SAV / CAPPUN2 / Favor / 1
Oppose / 2
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?

Bivariate Analysis: Examining the relationship between two variables.

Ex. 2) Does support for capital punishment vary by sex in the 1996 GSS subset?

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

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
male / female / total
Capital
Punishment / favor
oppose
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 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)

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
Fear / yes
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 whoare 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. ) in fear by sex, with ______of men expressing fear, in contrast to ______of women.

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
male / female / total
Capital
Punishment / favor / 82.6% / 71.6% / 76.6%
oppose / 17.4% / 28.4% / 23.4%
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. / CHI SQ
P / SIG?
YES/
NO / CRA-
MER’S
V / STRENGTH / I.V/DV
ATT1% / I.V/DV
ATT2
%
GSS96TAB
EXAMPLE / CAPPUN / SEX / P<.000 / yes / .129 / moderate / Male
82.6%
favor / Female
71.6%
favor
GSS96TAB / SPANKING / RACE
GSS96TAB / TRUST / SEX
GSS96TAB / GUNLAW / CAPPUN
GSS96TAB / FEWORK / SEX
GSS96TAB / VOTE92 / RACE
GSS72SAV / FEWORK / SEX
GSS72SAV / VOTE68 / RACE
GSS72SAV / CAPPUN / SEX

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?