Statistical Methods for Psychology

18.21 The study in Exercise 18.18 has an advantage over the
one in Exercise 18.17 in that it eliminates the influence
of individual differences (differences in overall level of
truancy from one person to another).

18.23 These are equivalent tests in this case.

756 Answers

Chi- Number
Stepa Effects Squarec df Sig. of Iterations

0 Generating Classb
Deleted Effect 1

1 Generating Classb

Deleted Effect 1

2

3

4

2 Generating Classb

Deleted Effect 1

2

3

3 Generating Classb

Deleted Effect 1

2

3

4 Generating Classb

Deleted Effect 1

2

5 Generating Classb

Deleted Effect 1

2

3

6 Generating Classb

aAt each step, the effect with the largest significance level for the Likelihood Ratio Change is deleted, provided the
significance level is larger than .050.
bStatistics are displayed for the best model at each step after step 0.
cFor “Deleted Effect”, this is the change in the Chi-Square after the effect is deleted from the model.

Age 3 Motorveh 3 Helmet 3 Injury

Age 3 Motorveh 3 Helmet 3 Injury

Age 3 Motorveh 3 Helmet,

Age 3 Motorveh 3 Injury,

Age 3 Helmet 3 Injury,

Motorveh 3 Helmet 3 Injury

Age 3 Motorveh 3 Helmet

Age 3 Motorveh 3 Injury

Age 3 Helmet 3 Injury

Motorveh 3 Helmet 3 Injury

Age 3 Motorveh 3 Helmet,

Age 3 Motorveh 3 Injury,

Age 3 Helmet 3 Injury

Age 3 Motorveh 3 Helmet

Age 3 Motorveh 3 Injury

Age 3 Helmet 3 Injury

Age 3 Motorveh 3 Injury,

Age 3 Helmet 3 Injury,

Motorveh 3 Helmet

Age 3 Motorveh 3 Injury

Age 3 Helmet 3 Injury

Motorveh 3 Helmet

Age 3 Motorveh 3 Injury,

Age 3 Helmet 3 Injury

Age 3 Motorveh 3 Injury

Age 3 Helmet 3 Injury

Age 3 Helmet 3 Injury,

Age 3 Motorveh,

Motorveh 3 Injury

Age 3 Helmet 3 Injury

Age 3 Motorveh

Motorveh 3 Injury

Age 3 Helmet 3 Injury,

Age 3 Motorveh,

Motorveh 3 Injury

.000 0

.065 1 .798 2

.000 1 .994

.181 1 .670 2

.768 1 .381 2

4.737 1 .030 2

.074 1 .785 2

.074 2 .964

.226 1 .634 2

.723 1 .395 2

4.688 1 .030 2

.301 3 .960

.870 1 .351 2

4.576 1 .032 2

.002 1 .966 2

.303 4 .990

.847 1 .358 2

4.573 1 .032 2

1.149 5 .950

4.576 1 .032 2

25.514 1 .000 2

25.604 1 .000 2

1.149 5 .950

Step Summary

Results for Exercise 17.7