Chapter III: Answers to the 2009
AP Computer Science A Exam
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Section I: Multiple Choice
Section I: Multiple Choice
O
Section I Answer Key and Percent Answering
Correctly
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Analyzing Your Students’ Performance on the
Multiple-Choice Section
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Diagnostic Guide for the 2009 AP Computer
Science A Exam
Listed below are the correct answers to the multiple-choice
questions, the percent of AP students who answered each
question correctly by AP score, and the total percent
answering correctly.
Section II: Free Response
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Comments from the Chief Reader
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Scoring Guidelines, Sample Student Responses, and
Commentary
Section I Answer Key and Percent Answering Correctly
Item
No.
Correct
Answer
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
A
A
D
C
A
A
D
D
C
D
A
B
C
D
B
C
B
A
D
E
5
4
3
2
1
Total
Percent
Correct
98
98
99
97
95
93
88
99
69
92
96
96
73
86
83
72
77
92
95
96
97
95
96
93
86
80
65
96
47
85
83
93
35
64
69
49
48
78
74
85
96
93
90
88
76
69
42
91
39
77
65
91
17
44
63
40
32
67
55
69
96
89
84
81
73
60
28
85
31
74
47
88
8
37
58
36
19
61
41
58
79
73
50
56
53
30
16
63
20
49
27
57
13
23
44
36
10
42
19
30
92
89
81
81
76
65
50
85
42
74
64
82
33
52
63
48
39
68
57
67
Percent Correct by Score
Percent Correct by Score
Item
No.
Correct
Answer
5
4
3
2
1
Total
Percent
Correct
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
B
E
C
A
C
D
C
B
D
E
C
B
C
A
E
C
E
C
E
D
83
88
93
96
47
91
90
88
84
93
88
86
80
67
92
37
63
44
41
52
66
71
83
88
23
75
61
68
71
79
68
62
58
41
76
20
29
25
19
25
56
56
75
78
19
62
34
52
52
61
61
47
37
28
61
13
12
19
12
15
47
44
66
71
20
54
23
44
37
45
57
37
27
22
54
14
7
18
8
11
31
20
50
44
20
29
15
25
18
21
46
25
15
14
31
19
6
16
5
8
56
56
73
74
27
61
47
56
53
60
64
52
45
36
63
22
26
25
18
24
89
Analyzing Your Students’ Performance on
the Multiple-Choice Section
If you give your students the 2009 exam for practice, you
may want to analyze the results to find overall strengths and
weaknesses in their understanding of AP Computer Science
A. The following diagnostic worksheet will help you do this.
You are permitted to photocopy and distribute it to your
students for completion.
1. In each section, students should insert a check mark for
each correct answer.
2. Add together the total number of correct answers for
each section.
90
3. To compare the student’s number of correct answers for
each section with the average number correct for that
section, copy the number of correct answers to the
“Number Correct” table at the end of the Diagnostic
Guide.
In addition, under each item the percent of AP students
who answered correctly is shown, so students can analyze
their performance on individual items. This information
will be helpful in deciding how students should plan
their study time. Please note that one item may appear in
several different categories, as questions can cross over
different topics.
Diagnostic Guide for the 2009 AP Computer Science A Exam
Programming Fundamentals (Average number correct = 17.43)
Question #
Correct/Incorrect
Percent of Students
Answering Correctly
Question #
Correct/Incorrect
Percent of Students
Answering Correctly
1
2
3
4
6
7
8
9
10
11
12
13
14
15
17
92
89
81
81
65
50
85
42
74
64
82
33
52
63
39
18
19
20
21
23
26
27
29
32
33
34
35
36
37
40
68
57
67
56
73
61
47
53
52
45
36
63
22
26
24
Data Structures (Average number correct = 3.97)
Question #
Correct/Incorrect
Percent of Students
Answering Correctly
3
4
11
17
27
34
36
37
81
81
64
39
47
36
22
26
Logic (Average number correct = 2.54)
Question #
Correct/Incorrect
Percent of Students
Answering Correctly
18
20
28
31
68
67
56
64
Algorithms/Problem Solving (Average number correct = 8.83)
Question #
1
2
3
6
7
8
12
14
15
17
22
25
27
28
Correct/Incorrect
Percent of Students
Answering Correctly
92
89
81
65
50
85
82
52
63
39
56
27
47
56
Object-Oriented Programming (Average number correct = 4.14)
Question #
Correct/Incorrect
Percent of Students
Answering Correctly
5
16
22
23
24
25
30
76
48
56
73
74
27
60
91
Diagnostic Guide for the 2009 AP Computer Science A Exam (continued)
Recursion (Average number correct = 0.74)
Question #
Correct/Incorrect
Percent of Students
Answering Correctly
13
39
40
33
18
24
Software Engineering (Average number correct = 0.25)
Question #
Correct/Incorrect
Percent of Students
Answering Correctly
38
25
Case Study (Average number correct = 2.86)
Question #
Correct/Incorrect
Percent of Students
Answering Correctly
21
22
23
24
25
56
56
73
74
27
Number Correct
Programming
Data
Fundamentals Structures
Number of
Questions
30
8
4
14
7
3
1
5
Average
Number
Correct
17.43
(58.1%)
3.97
(49.6%)
2.54
(63.5%)
8.83
(63.1%)
4.14
(59.1%)
0.74
(24.7%)
0.25
(25.0%)
2.86
(57.2%)
My Number
Correct
92
Logic
Algorithms/
Object-Oriented Recursion Software
Problem
Case Study
Programming
Engineering
Solving