distribution
n. the relation between the values that a variable may take and the relative number of cases taking on each value. A distribution may be simply an empirical description of that relationship or a mathematical (probabilistic) specification of the relationship. For example, it would be helpful in examining the distribution of scores for a college exam to view the frequency of students who achieved various percentages correct on the exam. In a normal distribution, most of the scores would fall in the middle (i.e., about 70% correct or a score of C), with fewer students achieving a D (i.e., 60–69% correct) or a B (i.e., 80–89% correct) and even fewer earning 59% or less (i.e., an F) or 90% to 100% (e.g., an A). See also frequency distribution; probability distribution.