Frequency of Scores Forming a Normal Curve

If 100 people take a test and the score for each is marked by an x on a graph, the result could suggest a normal curve. In a normal distribution most scores are at or near the mean (in this case, 50) and the number of scores further from the mean progressively decreases. (Source: From R.E. Slavin, Research Methods in Education, 2E, 1992, Allyn & Bacon. All rights reserved.)