CMSC 434/828S - Fall 2003
Prof Guimbretiere

Introduction to Human-Computer Interaction


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Homework #7:
(Due 12/09/03)

Measuring Fitts' law using a mouse

Overview

For this homework you will build a simple interface to measure Fitts' law parameters. For this simplified experiment, you will measure how fast a user can point between 2 squares shown on the screen for different value of the index of difficulty (ID). 

What you have to do

  • Design the experimental protocol to run the study.

  • Design a simple interface to measure Fitt's law parameters.  The interface should: 

    • for each trial, present a start-up screen so that the user can get ready,

    • for each trial, present a pairs of squares on the screen and let the user first click inside the left most square then click back and forth between the 2 squares as fast as they can for at least 10 times (users need to click inside the square each time),

    • for each trial, record the time it took the user to click between the 2 square (10 samples are recorded),

    • present a series of trials spanning the index of difficulty from 2 to 6. For each index of difficulty, your program should measure at least 3 possible width/distance combinations. Since you are recording 10 action per condition, your system should at least record 150 trials per users,

    • for each trial, present a completion screen,

    • present a completion screen at the end of the test.

  • Implement your design. See below for the implementation guide lines,

  • Run your protocol for at least 5 different users. (If you are using fellow students as subjects you don't need to apply for a human subject protocol review),

  • Write a report describing your experimental findings.

Implementation

For this project, you have to choose the specifics of how to implement your project within certain limits.

Platform

All projects must be able to run under Windows 2000 (or NT), or Windows 98. You can expect that the machine you will be running your project on will have a Java 2 virtual machine, and can execute Flash web pages. Finally you can expect the computer to have at least a CD-ROM drive.

Software

You are free to pick any programming languages (C++, Virtual Basic, C#, Java, Flash, Director...) and development environment you wish as long as the resulting program runs on the configuration described under the Platform section.
 

Deliverables

Your homework should contain: 

  • (40 points) A description of your protocol including:

    • your hypothesis,

    • the independent and dependent variables,

    • the possible confounding variables in your setting,

    • your target population and the consent form you used,

    • how you ran each subjects (including the check list followed by the experimenter)

  • (20 points) The executable code (in running order),
    Please, specify accurately your platform, operating system, language used, needed software, which file to run.

  • (20 points) A presentation of your experimental results including the problems you encountered during the experiment,

  • (20 points) An explanation of the discrepancies between predicted and measured times.

No statistical analysis is necessary for this homework.