1. Explain the difference between consistency and compatibility using examples from your experiences with software interfaces.

Answers will vary. The important distinction to make is that consistency has to do with how the steps needed to carry out one task (using one portion of the interface) relate to the steps needed for another task, while compatibility reflects how well interface operations match up with those in other products or in the "outside world."

An example could be that in Excel, the actions needed to calculate a sum and an average are almost identical: in the cell where the sum/average will be displayed, you indicate that the formula should be "SUM(" and highlight the cells to be summed,; all that changes to compute the average is that you specify a different function name. While this is compatible with the way things are done in Lotus, it is not particularly compatible with the "outside world," where a sum just requires successively adding values, while an average requires adding them, then counting how many values there were, then dividing the sum by the count.

2. Which user resources are involved in each of the following types of software use?

• playing a computer game involving a joystick
• watching a video clip on your computer screen
• typing a letter using word processing software
• composing music using a software package

• playing a computer game involving a joystick: involves eyes to watch the screen plus hands on the joystick (and possible ears, if audio is involved)

• watching a video clip on your computer screen: eyes to watch the screen and ears to hear the audio track

• typing a letter using word processing software: eyes to watch the screen, plus hands on the keyboard

• composing music using a software package: eyes to watch the screen, ears to hear the tones echoed back, plus hands on the keyboard and/or mouse

6.Name three ways that Visual Basic prioritizes the functionality and information presented to the user.

VB uses the concept of priorization extensively. Examples include:

1. There are many separate menus and they are organized hierarchically, so the user sees only a small subset of functionality at a time.

2. Complex operations are grouped together and presented in separate popup dialogs; they remain invisible until they are needed, and disappear once the operation is complete.

3. Toolbars (at top and side) present the most commonly needed features.

4. Separate windows control the source code and the form appearance; only one is shown at startup; the user must explicitly bring up others.

5. Since project groups may be very complex, a "project explorer" pane is used so that only one project is visible at a time; the user navigates through the hierarchy in this pane to see other projects.

6. Since a project potentially has many objects, each with its own properties, the properties pane shows only one object at a time; the user switches objects using the drag-down list at the top of the pane.

7. Debugging windows are not normally displayed, but are always available; once the user invokes them, they continue to come up even after the program has been stopped and then re-started -- this is an example of using mode to prioritize functionality and information.

center>Questions from Chapter 4

5. List three reasonable user requirements for the automatic translation software.

• It must be possible for the user to view either the original and the translated text, or to switch back and forth between them.

• It should be possible to determine which sentence in the original document corresponds to a sentence in the translated version.

• It should be possible to translate Spanish that includes idioms from different Latin American countries, as well as the kind of Spanish used in Spain proper.

6. For any one of the user requirements you just identified, define two usability criteria that could be tested empirically.

Examples corresponding to the first requirement:

• Displays must be capable of using English or Spanish character sets, and switching between them without an obvious pause.
• For documents less that 1 Mb in length, it should be possible to switch back and forth between the English and Spanish display in less than 1 second.