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?!?!)