AP Computer Science

Setup

Test Taking Tips

Practice FRQ

Setup Help

Outline

• AP Central Exam Readiness

PC or Mac or School Chromebook

• Login
• Setup
• Practice (if time)
• FRQ Scoring
• Test Taking Hints
• Practice FRQ (20 minutes)
• Use the Scoring Guide to Grade FRQ

Scoring

1-Point Penalty

- Array/collection access confusion ([] get)

- Extraneous code that causes side-effect (e.g., printing to output, incorrect precondition check)

- Local variables used but none declared

- Destruction of persistent data (e.g., changing value referenced by parameter)

- Void method or constructor that returns a value

No Penalty

o Extraneous code with no side-effect (e.g., valid precondition check, no-op)

o Spelling/case discrepancies where there is no ambiguity*

o Local variable not declared provided other variables are declared in some part

o private or public qualifier on a local variable

o Missing public qualifier on class or constructor header

o Keyword used as an identifier

o Common mathematical symbols used for operators (× • ÷ < > <> ≠)

No penalty

[] vs. () vs. <>

o = instead of == and vice versa

o length / size confusion for array, String, List, or ArrayList; with or without ()

o Extraneous [] when referencing entire array

o [i,j] instead of [i][j]

o Extraneous size in array declaration, e.g., int[size] nums = new int[size];

o Missing ; where structure clearly conveys intent

No Penalty

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o Missing { } where indentation clearly conveys intent

o Missing ( ) on parameter-less method or constructor invocations

o Missing ( ) around if or while conditions

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No Penalty Notes

*Spelling and case discrepancies for identifiers fall under the “No Penalty” category only if the correction can be

unambiguously inferred from context, for example, “ArayList” instead of “ArrayList”. As a counterexample, note that if the code declares “int G=99, g=0;”, then uses “while (G < 10)” instead of

“while (g < 10)”, the context does not allow for the reader to assume the use of the lower-case variable.

Exam Tips

• Problems are usually placed on the exam in order of perceived difficulty.
• However, some topics that are generally considered difficult might be easier for you than some others; make sure you allow yourself time to try all problems.

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• Glance at your watch periodically, especially if you find yourself having difficulties or getting distracted. That should help to get you back on track!
• Consult the Quick Reference documents during the exam. Be sure to call all methods with the correct parameters.

More Tips: Multiple-Choice Questions

• Work backwards, if possible, to eliminate some answers.
• Read all of the answers before making your final decision.

Free-Response Questions Make sure you have answered the problem.

• As you first read the problem, underline, circle, or star important details.
• Watch out for "You will receive no credit if..." or "You will not receive full credit if..."
• Reread the problem definition after you think you've finished writing the code, paying close attention to the details you marked.
• Write your code to satisfy the formal definition of the problem, but check your code with all the examples provided.
• They are usually chosen by the test developers to illustrate some of the special cases, and you're wasting a valuable resource if you ignore them.)
• Sometimes the pre-conditions and post-conditions outline the algorithm to solve the problem. Do not ignore them.

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Never let the beginning of a problem prevent you from getting points at the end.

• Most problems have multiple sections, and sometimes the later sections are easier than the earlier ones.
• Frequently, you will be told that you may make calls to one or more methods that you were asked to write in previous sections of the problem.
• The instructions might say, for example, "Assume that [method] works as specified, regardless of what you wrote in part (a). Solutions that reimplement functionality provided by this method, rather than invoking it, will not receive full credit."
• The best solution will probably include a call to the method written in part (a).
• You may earn credit for calling the method correctly, even if the code for the method you wrote for part (a) was incorrect or blank.
• However, if you copy the code from that method into the new section, even if it's completely correct, you will not earn full credit for your code.

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Aim for clarity in your programming. �

• Organize, indent, assign meaningful variable names.
• If you accidentally omit a curly brace, but your indentation clearly conveys your intent, you'll be given the benefit of the doubt.)
• Remember that humans will be grading your work. Make it readable.
• Commenting will not help your score,
• Except perhaps if your code is confusing and the comment enlightens the reader about what you were trying to accomplish. (However, comments are not a substitute for correct code!)

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More Tips

• Never give a "recipe" for the answer. If you know how to do even part of the problem, write code for the part you know.
• Partial credit is often awarded for having the correct loop bounds, initialization in the presence of an attempt to sum values in an array, and so on.
• Credit is not given for writing a description of what you would do if you had time.
• Occasionally, you'll be asked to "justify your answer." You generally won't earn any credit without a justification -- a sentence or phrase is often sufficient.
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• If a reader finds two solutions to a problem the first one will be graded.

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Tips anyone

• Don't waste time copying the method header or pre- and post-conditions; start writing the code just below them.
• If you run out of room:
• Find a blank page and continue your code.
• Indicate clearly what you've done, both on the page where you started the response and on the page where you continued it.
• Avoid using classes that aren't specifically given to you as part of the exam and aren't part of the Java language or the case study.
• While you may have developed or used other classes in your AP course (such as date or sort), don't use them in your responses on the AP CS Exam. Good luck, and do your best!

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Don’t forget the Return

• Be sure to include the return statement when writing a method that is not a void method.

How the results translate to scores.

• Curve for 2004 exam
• Score Grade
• 63-80 5
• 49-62 4
• 39-48 3
• 32-38 2
• 0 – 31 1
• Need to score a 4 to count as a passing grade.

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Other notes about scores

• 98% of students that got at least 27 out of 40 on the multiple choice section received a 4 or 5 for the whole exam.

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Good Luck

• M
• Arrive by 12:30 for the 1:00 exam.
• Take the practice exams using your AP Central login before Tuesday!