Exam 1 Grade Distribution and Answers

IS 485, Professor Matt Thatcher

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Exam Distribution

0

1

2

3

4

5

95 - 100 90 - 94 85 - 89 80 - 84 75 - 79 < 75

Exam Grade

Nu

mb

er

of

Stu

de

nts

Mean:81.24

Std Dev: 12.59Median: 83

Min: 42Max: 95

3

Waterfall vs. Prototyping

Application Description

RequirementsSpecification

SystemDesign

Product

Initiation

Analysis

Design

Implement

DesignPrototype

Evaluate

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Problems with WF WF lacks user’s perspective

– technology-driven– focus is on the “client”, not the “user”– does not involve user until “implementation” stage

» sees user role as finding “bugs” in the code or other minor problems

WF has no feedback (sequential, not iterative)– groups “hand off” discrete deliverables to the next group in

the WF process» functional specs are frozen early in the process

– high cost of fixing errors » increases by factor of 10 at each stage » iterative design finds these earlier

5

Measuring Usability Easy to learn

– how long does it take for typical users to learn relevant tasks?

Easy to remember– how easy is it to remember from one session to the next?

Efficient to use– how long does it take to perform benchmark tasks?

Minimal error rates– how many and what kinds of errors are commonly made?– if they occur, is good feedback provided so users can recover

High user satisfaction (subjectively pleasing)– confident of success– visually pleasing

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Design Model and User Model

Design Model User Model

System UI

Users gets model from their background, experiences and the design elements of the UI

What if design & user models don’t match?

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Summary(continued)

Design Model User’s Model

System UIDesigner’s UI

design choices

User sees the design choices

User interprets UI elements based on her

characteristics and experiences

8

Make Things Visible (1/2)

Affordances– physical properties (shape, texture, color, etc.) of an

object that show functionality– appearance indicates how the object should be used

without the need for words, labels, instructions, etc.– the user know what to do instinctively– examples: chair, scissors, staple remover, “buttons”

(clickable), knobs, doors, British Rail partition

Complex things may need explaining, but simple things should not

9

Provide Good Metaphors Use of a concept or word from one setting

(e.g., real world) to convey meaning in another (e.g., digital world)– physical analogies (e.g., trash, spreadsheet, file cabinet)– cultural standards (e.g., color, words)

Help reduce cognitive load for user Use of metaphors in design should be

based on an understanding of user’s model Communicate that metaphor to the user

through the UI

10

Design Specialties

Information Architecture– encompasses

information & navigation design

User Interface Design– also includes testing &

evaluation

Information Architecture

User InterfaceDesign

Usability Evaluation

Information Design

Navigation Design

Graphic Design

11

Physiology of the Eye Lens is not color corrected

chromostereopsis, produces 3D effect

White Light

Lens

Retina(separated wavelengths)

12

Focus on Blue Light

Lens

Retina

Focus on Red Light

Lens

Retina

13

Implication of Chromostereopsis Spectrally extreme colors produce

eye strain (refocusing)

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Physiology of the Eye Composition of the eye

(retina), wavelength sensitivity

65%

2%33%

RodsB&W

Conescolor

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The Aging Process Lens tends to yellow and absorbs

shorter wavelengths– causing increased insensitivity to blue

Fluids in the eye suffer from reduced transparency– Perceive a lower level of brightness

Implications– don’t rely on blue for text or small objects– older users need brighter colors

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Heuristics of Good GUI Design(Jakob Nielsen)

H2-1: Visibility of system status H2-2: Match between system and real world H2-3: User control and freedom H2-4: Consistency and standards H2-5: Error prevention H2-6: Recognition over recall H2-7: Flexibility and efficiency of use H2-8: Aesthetic and minimalist design H2-9: Help users recognize, diagnose, and recover

from errors H2-10: Help and documentation

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Task Analysis Questions Who is going to use system? What tasks do they perform? What new tasks are desired? How critical are the tasks? How often do the users perform the tasks? What are the time constraints on the tasks? How are the tasks learned? Where are the tasks performed? How do users communicate with each other? What happens when things go wrong?

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Contextual Inquiry Way of understanding users’ needs &

work practices Master – apprentice model allows user to

teach us what they do!– master does the work & talks about it while working– we interrupt to ask questions as they go

The Where, How, and What expose the Why

“Think aloud” and “probing questions”

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Principles Context

– go to the workplace & see the work as it unfolds– people summarize in interviews, but we want details

Partnership– master-apprentice relationship, yes; other models,

no» avoid interviewer/interviewee (stops work)» set expectations at the start

– partnership allows more apprentice interaction» alternate between watching & probing (withdraw and

return)

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What Should Scenarios Look Like?

Say what the user wants to do (the goal), but not how the user would do it– allows comparison of different design alternatives

Scenarios should say who the users are– name names (John Berry)– characteristics of the users (e.g., job title)

Should be specific, short, and in the user’s words– forces us to fill out description with other details that become

important– provides enough information to complete the goal (e.g., John wants

to purchase a blue polo shirt - size medium - for less than $50.00. Please help him find a product that matches this description and purchase it.)

Should describe a complete job

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ImageHeadline

Headline Headline

Headline

Relate +Promote

Relate +Promote

Relate +Promote

Relate +Promote

High-Level Browse Categories

Search

Logo + value prop

BrowseFold

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Independent Evaluations

Aggregated List of ViolationsIndependent Severity Ratings

Summary Report with Avg Severity Ratings (SR)

Final HE Report with SR and Fix Ratings