CMSC434:  Introduction to Human-Computer Interaction

Sample solutions for Exam #2

1. B (2 points)

2. A (2 points)

3. D (2 points)

4. C (2 points)

5. (8 points total) (2 points answer) Broad and shallow.  (2 points each reason)Response time and number of errors increase as depth increases.  The deeper the tree, the more complex it is.  Shallower trees give superior performances.  Designers are encouraged to limit trees to 3 levels, when the depth goes to four or five, there is a good chance of users becoming disoriented or lost.  (5 points each tree)

6.

A. (4 points) Asynchronous distributed interfaces are those interfaces which allow users to interact in different places during different times.  Synchronous distributed interfaces are those interfaces which allow users to interact in different places at the same time.

B. (4 points total, 1 point each example)
Synchronous:  chat, texting, instant messaging, video/audio conferencing
Asynchronous:  e-mail, newsgroups, listservers, discussion boards, blogs, wikis, online and network communities

C. (6 points) Any reasonably explained answer.  You must have a short paragraph.

7. (8 points, 2 points each)
Increase server capacity, network, speed, and modem reliability
Improve user training, online help, and online tutorials
Redesign instructions and error messages
Protect against spam, viruses, and pop-up advertisements
Organize consumer protection groups
Increase research on user frustration
Catalyze public discussion to raise awareness

8.

A. (8 points total; 2 points each guideline, 2 points each explanation)
Choose meaningful, specific, distinctive names; “write” for printing is not very meaningful.
Limit the number of commands and ways of accomplishing a task; there are two ways to append files

B. (4 points, 2 points each guideline)
Provide consistent structure (hierarchy, argument order, action-object)
Support consistent abbreviation rules (prefer truncation to one letter)

9.

A. Problems: (6 points, 2 points each)
Increased cognitive load compared to pointing
Interference from noisy environments
Unstable recognition across changing users, environments, and time

B. Benefits (6 points, 2 points each)
When the speaker’s hands are busy
When mobility is required
When the speaker’s eyes are occupied
When harsh or cramped conditions preclude the use of a keyboard

10.

A. (6 points, 2 points each)
Previous experiences
Individual personality differences
Task differences

B. (4 points)
Situations which lead to a reduction of errors.  Slower pace for new users of a system.  Choke system during light use, so responds about the same during high usage.  Tasks that require more cognitive abilities.

11.

A. (8 points, 2 points each)
Be as specific and precise as possible
Be constructive: Indicate what the user needs to do
Use a positive tone:  Avoid condemnation
Choose user-centered phrasing
Consider multiple levels of messages
Maintain consistent grammatical forms, terminology, and abbreviations
Maintain consistent visual format and placement

B.

i. (2 points)
Unspecific. Manual reference should be avoided
Cell phone out of range.

ii.  (2 points)
Wording hostile and derogatory
Authorization Required:  Username/password mismatch

12. (8 points, 1 point each guideline, 1 point each example of correct guideline)
Refer to pages 510-514 for all the guidelines
Limit the number of colors.  Only display 16 different colors on the PDA.
Use color conservatively.  Use consistent color in menu display.
Recognize the power of color as a coding technique.  Highlight in red upcoming deadlines in the calendar.
Place color coding under user control.  Allow the user to change the color scheme of the display