Statistical Methods for Psychology

608 Chapter 16 Analyses of Variance and Covariance as General Linear Models

Estimated Marginal Means

Treatment Group

Dependent Variable: POSTTEST

Treatment group

Control

0.1mg

0.5mg

1 mg

2 mg

Mean

1.715a

2.333a

3.172a

2.381a

1.935a

Std. Error

.232

.223

.248

.248

.226

Lower

Bound

1.246

1.882

2.671

1.880

1.480

95% Confidence Interval

aEvaluated at covariates appeared in the model: PRETEST 5 4.8060

Upper

Bound

2.185

2.785

3.672

2.882

2.391

Mean

N

Std. Deviation

Mean

N

Std. Deviation

Mean

N

Std. Deviation

Mean

N

Std. Deviation

Mean

N

Std. Deviation

Mean

N

Std. Deviation

Treatment group

Control

0.1mg

0.5mg

1 mg

2 mg

Total

PRETEST

3.3770

10

1.3963

5.3870

10

3.4448

6.4944

9

2.3781

5.0450

8

1.6876

3.9430

10

1.2207

4.8060

47

2.3788

POSTTEST

1.0940

10

.5850

2.5860

10

1.5332

3.9056

9

1.4768

2.4850

8

1.1874

1.5600

10

.8765

2.2857

47

1.4947

Report

Exhibit 16.4 SPSS output for analysis of Conti and Musty data

Type III Sum

of Squares

82.644a

.347

38.341

9.224

20.125

348.327

102.769

Source

Corrected Model

Intercept

PRETEST

GROUP

Error

Total

Corrected Total

df

5

1

1

4

41

47

46

Mean

Square

16.529

.347

38.341

2.306

.491

F

33.673

.707

78.108

4.698

Sig.

.000

.405

.000

.003

Eta

Squared

.804

.017

.656

.314

Tests of Between-Subjects Effects

Dependent Variable: POSTTEST

aR Squared 5 .804 (Adjusted R Squared 5 .780)

(continues)