Distribution of the Scores of Twelve Students on a Statistics Exam

The horizontal axis lays out that portion of the scale of exam scores that includes all 12 of the listed values, and each student's individual score on the exam is represented by a box placed at the appropriate point on the scale. Thus, the box for student 'a' is placed at 61 on the scale, the box representing student 'b' falls at 69, and so forth. You will note that the scale of exam scores in Figure 2.1 is drawn as though it were an equal interval scale. For purposes of this example, we will assume that it is an equal interval scale. In fact, most of what we will be saying in this chapter pertains to distributions that derive from equal interval scales of measurement. It is also possible to speak of distributions in connection with ordinal scale and categorical measurement, but that is something we will save for later.The type of graph shown in Figure 2.1 is useful when you are interested in conveying detailed information about each and every measure in the distribution, though with larger numbers of measures it can become quite cumbersome. Besides, for most practical statistical purposes your interest is not so much in the individual identity of your measures as in the overall shape and texture of the distribution that they compose.