User Guide

539
Reliability An
alysis
Reliability
Analysis S tatistics
Figure 37-2
Reliability Analysis Statistics dialog box
You can select various statistics describing your scale and items. Statistics reported
by default include the number of cases, the number of items, and reliability estimates
as foll
ows:
 Alpha
models: Coefficient alpha. For dichotomous data, this is equivalent to the
Kuder-Richardson 20 (KR20) coefficient.
 Split-half models: Correlation between forms, Guttman split-half reliability,
Spearman-Brown reliability (equal and unequal length), and coefficient alpha
for eac
hhalf.
 Guttm
an models: Reliability coefficients lambda 1 through lambda 6.
 Paral
lel and Strictly parallel models: Test for goodness-of-fit of model, estimates
of error variance, common variance, and true variance, estimated common
inter-item correlation, estimated reliability, and unbiased estimate of reliability.