Access Type

Open Access Dissertation

Date of Award

January 2013

Degree Type


Degree Name



Education Evaluation and Research

First Advisor

Shlomo Sawilowsky



Descriptive Statistical Attributes of Special Education Data Sets



December 2013

Advisor: Dr. Shlomo Sawilowsky

Major: Educational Evaluation and Research

Degree: Doctor of Philosophy

Micceri (1989) examined the distributional characteristics of 440 large-sample achievement and psychometric measures. All the distributions were found to be nonnormal at alpha = .01. Micceri indicated three factors that might contribute to a non-Gaussian error distribution in the population. The first factor is subpopulations within a target population. The second factor is ceiling effects and the third factor is treatment effects that may change the location parameter, variability, or shape of the distribution.

This present study examined the distributional characteristics of special education assessments and determined whether these distributions were differently distributed than Micceri's distributions. Three hundred ninety five datasets were collected, examined and classified according to distribution shape. The classification findings were compared with Micceri's (1989) classification of achievement and psychometric distributions. The findings indicate that there were more classifications of special education datasets and these distributions were differently distributed. There were 258, or 65.31%, of special education distributions that were different than Micceri's (1989) distributions. One hundred thirty seven, or 34.67%, of special education distributions were similar to Micceri's distributions.