# A Web-based Computer Program for Determining Group Classification, page 4
of 4

In Example 3, the group means and the population base rates are equivalent,
but Group 1’s variability is 10 times larger than Group 2’s. The researcher
determined that correct classification of Group 1 individuals was five times
more useful than correct classification of Group 2 individuals (utility values
of +5 and +1, respectively). The researcher weighted incorrect classification
of Group 1 and Group 2 as equivalent and not very serious (both -1). There are
two cut-points such that scores greater than 8.44 and less than 11.56 should be
classified as Group 2; otherwise Group 1. Using these criteria, 88% of the Group
1 cases and 88% of the Group 2 cases are expected to be correctly classified.
Because of the relatively very small variance for Group 2, cases that are very
near the mean for Group 2 are highly likely to be from Group 2, while cases
farther from the mean in either direction are much less likely to be from Group 2.
Thus, overall classification accuracy is 88% even though the two population means
are identical.

**Example 3. Two cut-points.**

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Contact: Michael Healy or Dale
Berger

Last Modified: 9/24/2011

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