While a fool will ask questions that a wise man can never answer, a wise man will only ask questions

1
While a fool will ask questions that a wise man
can never answer, a wise man will only ask
questions that every fool can answer
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Empiricism

• Science starts with observation

An observation is a singular statement about the
physical world
This class is scheduled to start at 210 pm The
leaves in Ames turned from green to red to yellow
last Fall A raven was on my porch stoop this
morning
How do we get from singular statements to
universal statements?
3
Inductivism
Facts -gt Induction -gt Laws
Law water freezes at 0C at sea-level
Sir Francis Bacon 1561 1626
If a large number of As have been observed under
a wide variety of conditions, and if all those
observed As without exception possessed the
property B, then all As have the property B
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Critical Rationalism

• Science starts with theory

A theory is a framework that attempts to explain
some aspect of the physical world A hypothesis
is a singular speculative conjecture about the
physical world
The speed of light is 299,792,458 meters per
second Drinking red wine will reduce the chance
of a heart attack Red flashing icons will attract
a users attention
How do we know if a theory is correct?
5
Falsificationism
Scientific Method
Hypothesis
Sir Karl Popper 1902-1994
Prediction
Falsified
Conduct Test
New test needed
We never know if a theory is correct!
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Hypothesis Testing
Hypotheses must be falsifiable to be
testable Good hypotheses are
specific Survival of the fittest hypothesis
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Probing the User Experience

• Generate multiple mutually exclusive hypotheses
• Specify hypotheses in as much detail as possible
• Ask questions that will falsify your hypotheses

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Example Scenario

• Amazon has just deployed a new graphical user
  interface for its used book purchasing system.
  They quickly noticed a decrease in the number of
  purchases per minute by viewing the web server
  logs. The user experience team hypotheses that
  the users have misunderstood the auction user
  interface metaphor and are thus failing to place
  a final bid required to purchase the desired
  product. How could they test this hypothesis
  using a survey?

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Survey

• The user experience team quickly reverted to the
  traditional shopping cart interface but sent an
  email survey to those users who had a chance to
  test the new interface. In the survey, the team
  asked one simple question
• What type of bid would be required to make a
  purchase on the Amazon used book website?
• A) a bid
• B) a final bid
• C) other (specify) ____

10
Example Scenario

• Microsoft recently began selling the Zune
  portable music player. In an internal Microsoft
  memo from Bill Gates, the Zune sales have not met
  their expectations. He speculates that there is a
  problem with the Zune user experience.
• What are some hypotheses that could explain the
  lackluster sales?

11
Example Scenario

• Microsoft recently began selling the Zune
  portable music player. In an internal Microsoft
  memo from Bill Gates, the Zune sales have not met
  their expectations. He speculates that there is a
  problem with the Zune user experience.
• What are some hypotheses that could explain the
  lackluster sales?
• How can we test these hypotheses?

12
While a fool will ask questions that a wise man
can never answer, a wise man will only ask
questions that every fool can answer