Teachers and principals need to understand and be able to talk intelligently about statistics. They need to be able to clarify concepts and generalizations used in tests that measure student progress. Among the terms educators need to be able to explain are "mean,""average,""median,""validity,""reliability,""pilot studies," and "item analysis." Educators also need to be able to communicate the meanings of percentiles and standard deviations and the distinction between standardized and criterion referenced tests. Teachers, administrators, and measurement specialists should develop a booklet of major statistical concepts and generalizations to inform parents and others as to the meaning of these terms. (SLD)