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APCS FRQ Test Prep Tidbits
Ria Galanos
CS Teacher, Thomas Jefferson HS for Sci & Tech Reader, AP Computer Science, 2007-13
August 2013 APCS In-Service Fairfax County
Agenda
About the Free Response Questions
Topics – What’s Hot, What’s Not
Where to Find Practice Questions
My Approach to Solving the Problems
Let’s Practice – Sing Us a Song, You’re the Piano Man
How to Score a Problem
Why You Should Sign Up to Score 1000+ Exams
Introductions
Overheard: “All of my students get 4’s or 5’s on the exam.” Me: “Eeek! This doesn’t happen at my school.”
Name
School
How long you’ve been teaching APCS (include this year)
# of Sections, # of Students, % of Honors Students
Diversity (gender, ethnic, racial, and/or socioeconomic)
% of students who take the exam
Number of Exams
Results from the 2013 AP Computer Science A Exam
26,350
31,187
0
5,000
10,000
15,000
20,000
25,000
30,000
35,00019
8819
8919
9019
9119
9219
9319
9419
9519
9619
9719
9819
9920
0020
0120
0220
0320
0420
0520
0620
0720
0820
0920
1020
1120
1220
13
31
Approx. 19% growth from 2011 to 2012 and 2012 to 2013!
Score Distribution (1-5) (Percentage)
Results from the 2013 AP Computer Science A Exam
0 20 40 60 80 100
2004
2006
2008
2010
2012
2004 2005 2006 2007 2008 2009 2010 2011 2012 20131 33.1 34.2 34 34 33.7 29.9 27.1 28 29.10 25.502 9.5 10 7.7 9.6 9 8.1 8 8 7.80 6.903 15.2 15 14.4 14.6 13.9 13.1 14 14.2 15.60 14.004 23.6 23.1 22.1 22.7 21.7 25.6 24.8 25 24.20 26.705 18.6 17.7 21.8 19.1 21.7 23.3 26.1 24.8 23.30 26.90
35
About the Free Response Questions
Four free-response questions
Duration: one hour and 45 minutes (follows MC after about a 10-15 break). That’s just about 26 minutes per question.
Students can/should use the Quick Reference Guide
Worth 50% of the total points of the test
Questions scored on a 9-point scale (may include half points)
Each question’s total score is rounded up (if half points exist)
Count on one question being about Grid World (or Grid World-like)
Most typical question requires students to write a method for part A and another for part B. (Exceptions – write a full class, part C)
Things Students Should Know
Extract digits from an integer
Check consecutive elements in an array/ArrayList
Accumulate values in an array/ArrayList
Average elements in an array/ArrayList
Find the max/min of an array/ArrayList
Find the index of the max/min of an array/ArrayList
Swapping elements of an array
Things Students Should Know
How to expand an array
Reverse items in an array
Remove items from an ArrayList
Search for an element in an array/ArrayList using linear (sequential) search
Sort an array using selection sort
How to traverse a 2-D array from multiple directions
What You Should Know
Free Response Question Map
All legal Java is acceptable (no additional output)
No reimplementation of code without penalty
What’s Not Tested by the FRQs Recursion
Sorting (but some students choose to implement a sorting algorithm, not well, I might add)
For-each (enhanced) for loops
The primitive character data type
The switch statement, the do-while loop, continue in loops
The prefix form of ++ and -- operators (++k, --k)
Library classes (such as StringBuffer, Arrays, DecimalFormat, etc.), unless specifically listed in the subset
Checked exceptions and try-catch-finally statements
System.in and Scanner; any input and output other than System.out.print and System.out.println
enum data types
Where to Find Practice Questions
Live Questions
AP Audit Test
Teacher Created Questions – Brandon Horn, and others
JavaBat (aka Coding Bat) / Practice-It / CodeLab / Learneroo good for direction following, method writing
Caution: solutions posted online
My Approach
Teach them how to READ
Quickly review story
Examine question in part A first
Make note of class, method, and collection names
Underline what you are being asked to do
Note what the questions is asking you to return (if anything)
My Approach Continued
Look at preconditions and postconditions carefully
Check all code paths to make sure you return in all cases (if method is a non-void method)
Let’s Practice
First, individually
Second, talk with table partner
Third, group discussion
How to Score
Get to know the rubric
When in doubt, hose ‘em
Usage sheet
Scoring spreadsheet
Penalty for extraneous code with a side effect (including printing)
Grid World
Scavenger hunt
Use the reference guide for EVERYTHING
Get the grid!!!
Note the return types on the methods you use gr.get (some location) returns the actor at that location this.getLocation() returns a Location
You can override act in Bug, but NOT in Critter
Have students understand the difference between the processActors, getMoveLocations, selectMoveLocations, and makeMove methods
The APCS Exam Reading
Question: Why would I want to spend a week grading 1000+ exams?
Answer: Because grading is fun! (If you do it with your favorite adult beverage, ice cream, and 150 of your closest friends!)
All About the Reading
It is where the FRQs are graded each June.
Held in downtown Cincinnati since 2009. And the waterfront area just got a much needed facelift!
Usually held first week in June. Next up: June 2-8, 2014.
Participants read for 7 consecutive days. Two additional days are designated for travel.
In 2014, you would miss six days of school, 1 ½ weekends
150 of your closest CS friends engage in camaraderie, collegiality, and professional development.
How Reading is Organized
Readers: 50% current APCS teachers with at least three years of experience, 50% college CS faculty
First timers: (We ♥ acorns!) provided extra support
Tables: typically contain 3 pairs of Readers with 1 table leader
Each FRQ has its own room. Each room has multiple table leaders and four question leaders. Supervising the QLs is an Exam Leader. The big cheese is the Chief Reader (CR).
Readers are assigned to one of the four free-response questions.
Rubrics and Training
Prior to the pre-Reading:
The Chief Reader develops the rubrics and canonical solutions
At the pre-Reading:
Question leaders (QLs) vet the rubrics and develop reader training
Table leaders vet the training
Rubrics and Training Cont’d
Reader training:
Takes almost the whole first day
Be one with the rubric!
Group reading of the training pack
Split packs with table partner
Now on to the Reading:
Table leaders mentor readers
Consistency checks designed to support readers
After the Bell Rings
Walking/running groups, golf, museum tours
Designated social lounge at hotel open from 7-11pm
Planned evening events include: Professional Night Toy Night Puzzle Night Reds Game Closing Ceremonies
How Do I Sign Up?
Applications taken on a rolling basis.
Want to participate in 2014? Apply early (Oct/Nov)!
First-round invitations go out in early January.
Must have taught AP CS for three years (ok to be in third year).
Stipend is about $1700 (before taxes).
All travel, meals, and lodging are covered (bring $$$ for optional Starbucks, Graeters ice cream, and Cubs games).
1984 First Examination (Pascal) 1988 Exam split into A and AB (A subscore) 1992 A subscore eliminated 1995 First Case Study 1999 C++ 2004 Java 2008 First year of GridWorld Case Study 2009 Last year of AB exam 2014 Last year of GridWorld Case Study 2015 First year of AP CS A Labs
AP Computer Science Exam History
Results from the 2013 AP Computer Science A Exam 6
The Disappearing Bug Case Study
Grid World is going away – last tested in 2014
2015 will likely see a replacement of the Case Study
Current proposal: The Why & The Labs Magpie – Natural Language Processing
Conditionals, Loops, String Class Picture Lab – Pixel Manipulation
Two-dimensional arrays Game of Elevens
Interacting objects
Labs will NOT be tested on exam (What?!?!)