EDF5432
Spring 2002
Worksheet 2
Obtain values by using the five assumptions of Classical Theory, four different forms of
2
reliability, and the facts; a. 2 = T + 2 , and b. XY = X 'Y .
X
E
1.
a.
b.
c.
d.
Given X = 10 and E = 2, what is T? T = X E = 10 2 =

Factor Analytic Approach to Reliability
- Relationship to Coefficient
If we assume that all the items have the same , i.e., the same
factor loading or item discrimination power,
=
2
TX
2
X
( )
=
j
2
X
2
2
m 2 2 m 2 T
=2
2
X
X
=
The estimate of 2T is the

Reliability
Reliability = Indicator of how consistently (precisely) the test
measures the psychological construct.
Consistency of test results from one administration of the
test to another administration (test-retest reliability).
Consistency of rando