Path: janda.org/c10
> Overview
of SPSS
>
Analyze
>
ONEWAY

Statistical
Package
for the
Social
Sciences
Syntax for Analysis of Variance
Procedures

ANALYSIS OF VARIANCE
Several SPSS procedures test for statistically
significant differences in means for an
intervallevel dependent variable when analyzed by two or
more groups classified on a nominal scale. All of these
procedures conduct an analysis of variance and produce an
Fratio as the test statistic.
Like zscores and tscores, Fratios are interpreted
with reference to a table of critical valuessuch as the
F table on pages 710717 in Kirk. Note that the magnitude
of the F ratio must be interpreted with reference to
two degrees of freedom. One for the numerator in
the ratio and another for the denominator.
ANOVA is the general procedure for analysis of
variance in SPSS, but ANOVA involves ideas not covered in
our course. Instead, we will feature two very similar
procedures:
 ONEWAY is the basic procedure for analysis
of variance for intervallevel variables when analyzed
by one independent nominal variable.
 MEANS was developed just to compare means
for an intervallevel variable when brokendown into
categories of several levels of nominal variables. It
also generates an analysis of variance and produces
the useful eta^{2} statistic for explained
variance. I prefere MEANS over ONEWAY, but you should
know both.
The syntax for the ONEWAY and MEANS
commands are given below:

ONEWAY

"varlist" names the dependent
intervallevel variables to be analyzed. More than one
dependent variable can be analyzed on a given ONEWAY run.
Suppose that you wanted to analyze the percent of land
under cultivation (in the POLITY data the variable would
be landcult) across nations in the major regions
of the world.
"varname" names the single nominallevel
variable used to classify the several groups being
compared. For example, "Region" in the table below might
be the variable for the groups.
(min,max) indicates the range of values that
embrace the groups being compared. For the "Region"
variable in the POLITY dataset, specify (1,6).
REGION seven world regions (POLITY dataset)
Valid Cum
Value Label Value Frequency Percent Percent Percent
ANGLOAMERICAN 1 5 4.5 4.5 4.5
EUROPEAN 2 17 15.3 15.3 19.8
LATIN AMERICAN 3 23 20.7 20.7 40.5
ASIA 4 15 13.5 13.5 54.1
MIDDLE EAST 5 11 9.9 9.9 64.0
AFRICA 6 32 28.8 28.8 92.8
EASTERN EUROPE 7 8 7.2 7.2 100.0
  
Total 111 100.0 100.0


ONEWAY
varlist BY
varname
(min,max) .

ONEWAY output

oneway landcult by region
(1,7).

     O N E W A Y     


Variable LANDCULT % OF LAND
UNDER ACTUAL CULTIVATION

By Variable

REGION seven world regions



Analysis of Variance




Sum of

Mean

F

F

Source

D.F.

Squares

Squares

Ratio

Prob.

Between Groups

6

9047.7478

1507.958

8.3937

0

Within Groups

100

17965.2509

179.6525



Total

106

27012.9987





MEANS

"varlist" names the dependent intervallevel
variables to be analyzed. More than one dependent
variable can be analyzed on a given MEANS run.
"varname" names the multiple
nominallevel variables used to classify the several
groups being compared. For example, "Region" in the table
below might be the first nominal variable for the groups
and "country" might be the second.
The same variables analyzed under ONEWAY are used in this
analysis with MEANS:
2 means landcult by
region /statistics=anova.

  Description of Subpopulations  

Summaries of

LANDCULT : OF LAND UNDER ACTUAL CULTIVATION

By levels of

REGION seven world regions


Value Label

Mean

Std Dev

Cases

For Entire Population


18.5103

15.9637

107

REGION

1.00 ANGLOAMERICAN

12.4

11.7601

5

REGION

2.00 EUROPEAN

29

17.5879

16

REGION

3.00 LATIN AMERICAN

11.5217

10.3874

23

REGION

4.00 ASIA

24.8571

15.4016

14

REGION

5.00 MIDDLE EAST

17.7

15.5456

10

REGION

6.00 AFRICA

11.1065

10.9881

31

REGION

7.00 EASTERN EUROPE

40.0375

14.7235

8

Total Cases = 111


  Analysis of Variance  






Dependent Variable LANDCULT : OF LAND UNDER
ACTUAL CULTIVATION

By levels of REGION

seven world regions

Value Label

Mean

Std Dev

Sum of Sq

Cases






1.00 ANGLOAMERICAN

12.4

11.7601

553.2

5

2.00 EUROPEAN

29

17.5879

4640

16

3.00 LATIN AMERICAN

11.5217

10.3874

2373.7391

23

4.00 ASIA

24.8571

15.4016

3083.7143

14

5.00 MIDDLE EAST

17.7

15.5456

2174.98

10

6.00 AFRICA

11.1065

10.9881

3622.1387

31

7.00 EASTERN EUROPE

40.0375

14.7235

1517.4787

8

Within Groups Total

18.5103

13.4035

17965.2509

107







Sum of


Mean


Source

Squares

d.f.

Square

F

Between Groups

9047.7478

6

1507.958

8.3937

Within Groups

17965.2509

100

179.6525


Eta = .5787 Eta Squared =
.3349


MEANS
varlist BY
varname BY
varname ...
/STATISTICS
=ANOVA.

MEANS
output
