DECEMBER 2020
48 HOUR ASSESSMENT
SCHOOL OF COMPUTER SCIENCE

MODULE CODE:

CS5040
MODULE TITLE:

Human Computer Interaction Principles and Methods
TIME TO HAND IN: 48 hours

EXAM
INSTRUCTIONS
a. Answer all 3 questions
b. Each question indicates the number of marks it
carries. The paper carries a total of 60 marks.

This assessment consists of exam-style questions and you should answer as you
would in an exam. As such, citations of sources are not expected, but your answers
should be from your own memory and understanding and significant stretches of text
should not be taken verbatim from sources. Any illustrations or diagrams you include
should be original (hand or computer drawn). You may word-process your answers, or
hand-write and scan them. In either case, please return your answers as a single PDF.
If you handwrite, please make sure the pages are legible, the right way up and in the
right order. Your submission should be your own unaided work. While you are
encouraged to work with your peers to understand the content of the course while
revising, once you have seen the questions you should avoid any further discussion
until you have submitted your results. You must submit your completed assessment
on MMS within 48 hours of it being sent to you. Assuming you have revised the module
contents beforehand, answering the questions should take no more than three hours.








1. Experimental Design

(a) A user study was designed to assess the usability of three bespoke input
interfaces for a watch - pressure, twist and pan input. To characterize the
performance of each condition, the three interfaces were modified and
measures for two variables collected: input entry times and errors. The
experiment was conducted in a quiet lab and took between 40 to 60
minutes to complete. Before the study participants were debriefed and
demographics collected. The same participants took part in each condition
and the three interface conditions were balanced in a Latin- squared
design order. After completing the targeting task, participants rated the
perceived usefulness and usability of each interface using a 7-point Likert
scale.

(i) What makes this a controlled experiment? Identify the key elements
in this design which make it a controlled experiment (e.g.
experimental design, variables involved etc.)

[5 marks]

(ii) What type of statistical test might one use to compare the means of
the input entry times and why?
[2 marks]
(iii) What type of statistical test might one use to compare the perceived
usefulness ranking and why?
[2 marks]

(iv) Discuss the ecological validity of this experimental design for the
interfaces
[3 marks]
(v) With respect to the experimental design outlined in this question,
describe four prominent threats to experimental validity.
[4 marks]
(b) For each of the following experiments below, describe (i) a suitable
experimental design (within subjects, between subjects or mixed subjects
design) (ii) the independent variable(s), (iii) one dependent variable and
(iv) any skills transfer problems.
(i) The experimenter wants to test which of two spatio-temporal routing
visualization techniques (e.g. A 2D versus a 3D visualisation) is more
successful in terms of user speed and accuracy when navigating to a
destination. The same underlying map data is used in both
visualization techniques.
[2 marks]
(ii) The experimenter wants to test whether users type faster on a
keyboard if they type phrases drawn from particular sets of phrases
and for particular presentation styles.
[2 marks]
[Total marks 20]

2. Interaction Design and Evaluation

(a) TK SmartRun Inc. have hired you to develop a new wearable music player
for their new target customers, elite marathon runners. Create 2 personas
for this.

[4 marks]

(b) MokuTV inc. scenario
"You are hired by a company called ‘MokuTV inc.' to help them
understand their target audience. They are developing a product called
SmartTVdata and in this study they wish to determine if study
participants can detect different coloured objects on a 4K display if the
objects are large and occur on screen for a longer period of time (rather
than only being visible for a short duration). They aim to vary the object
colour, object size and object visibility duration and measure the detection
rate of each participant. MokuTV inc aims to show that with SmartTVdata
they can more efficiently transcode a video stream and not impact on the
user experience of the TV while vastly reducing bandwidth costs”
With respect to the MokuTV inc scenario, describe:
(i) How you would go about recruiting participants to participate in a
study while the product is still under early development.
[2 marks]

(ii) The precise details of a screener you would develop and how you
might use it in a recruitment process.
[2 marks]



(c) Compare and contrast mobile phone text entry with wrist-worn smart
watch text entry (consider issues such as usability, speed and accuracy).
[2 marks]

(d) A company has developed a prototype smartwatch that allows the user to
use the surrounding skin on their wrist as an extension of the watch screen
for visualisations and interaction.

(i) Describe four issues (for novice and first time use) a HCI professional
should consider when incorporating the novel interaction technique
into their smart watch.
[4 marks]
(ii) Researchers decide to evaluate the prototype for the success of user
interaction. Describe the advantages, disadvantages and
appropriateness of a laboratory study versus a field study to evaluate
this form of input.
[4 marks]

(iii) Suggest two metrics you would consider for the evaluation of the
interaction technique and explain how would you use them in the
study.
[2 marks]
[Total marks 20]

3. Qualitative and Quantitative Analysis:

(a) Critically appraise this interview about Microsoft Teams, labelled “MS
Teams Interview”. Ensure you comment on each of the following (i)
question strength or weakness and (ii) interview structure/approach.

[4 marks]
Numbered lines with Interviewer speaking labelled (I), interview subject reply
(S).
[Interview starts at 14.22.00]
1. I: So, everyone uses Teams now, how many people call you on Teams each
day/week?
2. S: About 10 people but I use it to send text messages to friends every few
hours
3. I: Don’t you think we should just have Teams on phones instead of
traditional calls?
4. S: Errrr, I guess so, yes
5. I: Ok, when you started using Teams what made it most interesting for you?
6. S: Gosh, errr, it’s been a while. I think I had to use it when I was working in
Australia a few years ago but it’s hard to say.
7. I: Rate from 1 to 4 the most important features of Teams to you, where 1 is
least important and 4 is most important.
8. S: Video Calls (1), Audio Calls (3), Text Messages (4), Sending File/Images (2)
9 I: Which of these new features is most important to you? Online gaming
integration, AR Emoji or setting up a smart avatar, which can reply to
incoming, calls for you?
10: S: If I had to pick, I guess the avatar but I’m not quite sure how that might
work
11: I: Does Teams do anything that’s particularly useful to you in a way that it
might not have been designed for? If so, what is it? What makes it useful?
12: S: Oh yeah, my wife thinks this is crazy but I use it for keeping our weekly
shopping list.
13: I: Thank you for your time and we will report back to you our overall results
[Interview ends at 14.26.14]
MS Teams Interview

(b) Name an approach that a researcher could use to analyse the qualitative
data gathered from interviewing people about their use of MS Teams, and
an advantage that using this approach would bring.
[2 marks]
(c) A museum is developing an Augmented Reality device for visitors to
interact with exhibits and enhance their experience of the museum space.
The device will be given to visitors at the main entrance desk and returned
at the end of their visit. The curators of the museum intend to use the
device to help them plan improvements to the physical space of the
museum.
A researcher has been asked to evaluate the prototype device. The
researcher plans to carry out a questionnaire survey of museum staff and
visitors to gather quantitative data about them and their use and opinions
of the system.
Describe how the researcher might analyse the quantitative data collected
from the questionnaire surveys collected from staff and visitors to the
museum.
[5 marks]
(d) With respect to Fitts’ law: we test two new computer mice (mouse A and
mouse B) with 128 participants. Each participant uses each mouse in a
reciprocal Fitts’ law task.
(i) For device A, given an SSerror of 1,000 and an SStotal of 20,000, what
is the coefficient of determination (R2) and how do you interpret the
result?
[1 mark]
(ii) For device B, given an SSerror of 20,000 and an SStotal of 100,000,
what is the coefficient of determination (R2) and how do you
interpret the result?
[1 mark]
(iii) Which R2 is higher and what does this allow us to say about device
A versus B?
[1 mark]
(e) In a between-subjects experiment we collect the following errors for
Keyboard A and Keyboard B.
A B SSA SSB SSA+B
4 10 4 4 26
7 13 1 1 20
9 16 9 16 49
7 10 1 4 5
3 11 9 1 40
Mean 6 12 Sum 24 26 140
Mean A+B 9

The Keyboard A group has 3 participants and Keyboard B has 3. There are
10 participants in total. Given the above table of values, answer the
following questions with respect to a one-way analysis of variance
(ANOVA) for a between-subjects design with two levels of a single
independent variable).

(i) With an ANOVA there are two independent estimates of the
population variance that can be obtained. What are these estimates
and how are they related?
[1 mark]
(ii) The SStotal is 140 so what are the values for SSerror and SSeffect?
[1 mark]
(iii) There are 10 participants in total spread over 2 groups so what are
the values for dferror, dfeffect, MSerror and MSeffect?
[2 marks]
(iv) With an α Confidence Level of 0.05 and hence a critical value of 5.32,
what is the F-ratio value, and what is the test significance at this
level? And what does this mean?
[2 marks]
[Total marks 20]

*** END OF PAPER ***


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