### AP STATISTICS, 1998

Richard L. Scheaffer
University of Florida

Newsletter for the Section on Statistical Education
Volume 5, Number 1 (Winter 1999)

Overview of the 1998 Examination

While only in its second year of operation, the AP Statistics program produced 15,200 operational exams and 250 alternate exams in 1998, double the number for 1997. The 1998 exam was of the same structure as the 1997 exam, with 35 multiple choice and six free-response questions. As in 1997, many students found the multiple choice questions to be relatively easy and the free response questions to be quite challenging. Student performances were roughly equivalent to those of 1997 on the equating multiple choice questions, but the average score on all multiple choice questions decreased in 1998. (The multiple choice questions were deemed too easy in 1997, and an attempt was made to make that section a little more difficult in 1998.) Even though the answers to the free-response questions are not at the level the Test Development Committee would like to see, they were somewhat better than last year in the sense that the mean score increased slightly, nearly doubling on the Investigative Task. The efforts by the Committee, the College Board and ETS to disseminate information on what is expected in answers to free- response questions appears to be having a positive effect, and these efforts should continue unabated. Statistical Summaries Table 1 shows the summary statistics for the raw scores for 1997 and 1998, based on a total of 50 points for each of the sections, multiple choice and free response. Notice that the standard deviations are large compared to the ranges of these scores.

Table 1 Summary Statistics on Raw Scores for AP Statistics

 COMPOSITE OBJECTIVE FREE-RESPONSE MEDIAN 1997 1998 47 44 31 27 15 16 MEAN 1997 1998 46.8 44.2 30.4 26.6 16.5 17.7 SD 1997 1998 18.9 19.6 10.4 10.3 9.610.5

Table 2 shows the results of the grade-setting process, turning the raw scores into an AP grade. The percentages in each of the five grade categories are similar to those of 1997, as are the cut points, but there is a slight decrease in the percentage of students receiving an AP grade of 5.

Table 2 Grades, Boundary Scores and Percentages for AP Statistics

 Grade 1997 Minimum Score* 1997 Percentage of Students 1998 Minimum Score 1998 Percentage of Students 5 4 3 2 1 68 54 41 29 0 15.7 22.1 24.4 19.7 18.0 68 53 39 28 0 13.5 21.3 24.6 18.7 21.9

*Lowest composite score to qualify for that grade, out of 100 total points

Table 3 provides the average composite score for students in each of the AP grade categories.

Table 3 Mean Composite Score by AP Grade, 1998

 AP Grade CompositeScore 54321 75.52 59.53 45.39 33.30 17.77

Conclusion

It appears that AP Statistics has attracted the attention of teachers, students and the community of professional statisticians. Students with AP experience in statistics are beginning to show up in colleges and universities around the country. It would be interesting to see how well they perform in follow-up courses; the AP Statistics Development Committee would be happy to hear such reports from the college and university teachers of the next statistics course these students might take. If more information is desired on the AP Statistics exams themselves, Educational Testing Service (ETS) will be releasing a report, with sample student solutions, on the free-response questions for 1998 and the entire 1997 exam sometime by early 1999.