23 April 2019
Question 1
a) Explain the meaning of effectiveness, efficiency, and satisfaction from the perspective of
Usability.
Effectiveness is the completeness and accuracy with which users achieve specified
goals. It is determined by looking at whether the user’s goals were successfully met
and whether all works are correct.
Efficiency is concerned primarily with how quickly a task can be completed
Satisfaction is the comfort and acceptability of the work system to its users and other
people affected by its use.
b) Briefly explain how a product with good usability can be beneficial to the users and
developers.
Benefits to the USERS
o Increased productivity
o Reduce learning time
o Reduced errors
o Reduced stress
Benefits to the DEVELOPERS
o Minimize the cost of customer support
o Reduce the time needed for training
o Good reputation
c) What is Persona? Discuss why it is an important tool at the analysis stage of Human
Computer Interaction framework.
Persona is user models that are represented as specific, individual human beings. They
are not actual people but are synthesized directly from observations of real people.
Because in analysis stage, persona can be used to describe a common user that will be
using the system and allows the developers to know what to do in the next stage.
d) Discuss why Hierarchical Task Analysis (HTA) is an important tool.
To understand the way user perform their current job with an existing system.
By understanding what the user has been doing, a new system can then be arranged in
a way that is compatible with the user’s behaviors.
Advantages:
- Skill learned from the old system can be transferred to the new system.
- User doesn’t need to alter his/hers approach significantly when using the new
system.
Question 2
a)
STM LTM
CAPACITY Limited Unlimited
ACCESS Fast Slow
DECAY Fast Slow
b) Explain THREE usages of sounds. Give an example for each usage.
As a means to locate things
As a means to provide feedback
As a means to attract attention
c) Explain how you could improve the usability of a website by applying the Fitt’s law.
Keep interface items that are similar close to each other to reduce the distance
between them.
For important features to let user to know, design the button bigger than the usual
ones.
Grouping similar buttons that are related together.
d) Briefly explain Gulf of Execution and Gulf of Evaluation.
Question 3
a) Error Messages Design
Explicit – indication that something has gone wrong.
Human-Readable – expressed clearly in plain language using words, phrases and
concepts familiar to the user rather than in system-specific terms.
Polite – phrase that doesn’t blame users or imply that they are either stupid or doing
something wrong.
Precise – describe the exact problem.
Constructive – provide advice on how to fix the problem
b) Explain the following interaction styles and give ONE example for each of them.
i) Instructing – Issuing commands and selecting options.
ii) Conversing – Interacting with a system like having a conversation.
iii) Manipulating – Interacting with objects in a virtual or physical space.
iv) Exploring – Moving through a virtual environment.
Question 4
a) Explain the following methods of building prototype.
Throw-away
o The prototype is built and tested. The design knowledge gained from this
exercise is used to build the final product, but the actual prototype is
discarded.
Incremental
o The final product is built as separate components, one at a time.
o There is one overall design for the final system, but it is partitioned into
independent and smaller components.
o The final product is then released as a series of products, each subsequent
release including one more component.
Evolutionary
o Evolutionary prototype is not discarded and serves as the basis for the next
iteration of design.
o In this case, the actual system is seen as evolving from a very limited initial
version to its final release.
b) Explain THREE benefits of using usability metrics in system design.
Track progress between releases
Assess your competitive position
Make a stop/go decision before launching system.
c) Define Satisfaction and how it could be measured.
Satisfaction is composed of comfort and acceptability of use.
Measured by:
o Percentage of customers who would recommend it to a friend after two hours
use.
o Percentage of customers that rate the product as “more satisfying” than a
pervious product.
d) Explain why we need more than 5 users for quantitative usability studies.
In order to get a high confidence interval on the results, it is recommend testing 20
users for each design.
9 February 2019
Question 1
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