Transcript Are There Rival Causes?

Are There Rival
Causes?
CSIT58 Chapter 10
Rival Cause
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Another reasonable interpretation that can
explain why a certain outcome occurred.
The same evidence can be consistent with
different analysis.
Clues for Detecting Rival Causes
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Can I think of any other way to interpret the
evidence?
What else might have caused this act or these
findings?
If I looked at this from another point of view,
what might I see as important causes?
If this interpretation is incorrect, what other
interpretation might make sense?
The Cause or A Cause
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A common error is to look for a simple, single
cause of an event when it is really the result of
many contributory causes.
Only 18 percent of U.S. households currently
subscribe to broadband Internet services such
as cable modems or DSL, according to TNS
Intersearch. Most people are satisfied with their
dial-up connections.
The Cause or A Cause
People may be sticking with their dial up
connections for any or all of the following
reasons:
 Reliable
broadband is not available in their area
 They don’t understand the advantages of
broadband
 Broadband is more expensive to install with
higher monthly charges.
 Their older computer is not equipped for a
broadband connection.
Differences Between Groups
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Researchers find differences between groups
and conclude that the differences support their
hypothesis.
Ms. Lane’s online CIS1 students have higher
total scores on average than the night face-toface CIS1 class. Both classes are given the
same assignments and tests. Online learning is
more effective for introductory computer classes.
Differences Between Groups
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Problem: research groups almost always
differ in more than one important way.
 Students
who sign up for an online class may
be more familiar with computers to start with.
 Students who are successful in online classes
have to be self-motivated and may get higher
grades in general.
 Students who take courses at night may have
less time to spend and the 3 hr class time is
very long to pay attention.
Confusing Causation with
Association
We have a tendency to “see” events that
are associated, or that “go together” as
events that cause one another.
 Conclude that because characteristic X is
associated with characteristic Y, that X
therefore causes Y.
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Women in Computer Fields
"Usually starting around the middle school years
and puberty, girls start to get a message that
computing is for boys," said Jo Sanders, director
of the Computer Equity Expert Project, a New
York-based group that received federal funding to
train computer teachers in how to reach girls. "If
there's a computer club after school, they see
boys there. If they walk by a computer store
downtown, the salespeople are men. If they see
ads for computers, the people in the ads are men
... .They get the idea that computing is male”
DeBare, Ilana. “Computer Classes Lack Key
Feature: Girl’s Faces.” SACBEE. 1996.
http://www.sacbee.com/static/archive/news/projec
ts/women/wcschools.html (12 Nov. 2002)
Possible Explanations
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Explanation 1: X is a cause of Y
Girls don’t like to study computers because role
models are male.
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Explanation 2: Y is a cause of X
The role models are male because girls don’t
like to study computers.
More Possible Explanations
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Explanation 3: X and Y are associated because
of some third factor Z
"The image of the computer scientist as a 'nerd'
was something I heard a lot about from my
daughters," said Anne-Louise Radinsky,
chairwoman of the computer science department
at California State University, Sacramento. "I think
the image was very much a problem for them."
Factor Z is the “nerd” factor.
More Possible Explanations
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Explanation 4: X and Y influence each other:
For girls who do venture into computer science
classes, the small numbers can be discouraging.
Dok Lam, a 16-year-old junior at San Juan High
School, almost dropped out of Grant McMicken's
programming class when she realized she was
practically the only girl. "I said, 'I don't think I
belong here, it's all guys,'" Lam recalled.
Girls don’t study computers because it’s all male,
and it’s all male so girls don’t study computers!
Confusing “After this” with
“Because of this”
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Try to explain an event by saying:
Because event B followed event A, then event
A caused event B.
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Also called post hoc fallacy
Chain of Events
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Many events that occur close together in
time do not do so because one causes the
other.
Hewlett Packard’s stock price went from
over 60 when Carly Fiorina became CEO
in July 1999 to 28 today. Putting a woman
in charge ruined the company.
(Fall 2005)
Truth or Coincidence?
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Timing of events may be just a coincidence. Or
there may be a real connection!
 The
prices of most technology stocks have declined
since 1999. Can we be sure that HP’s stock price is
due to Ms. Fiorina’s mismanagement?
 Maybe there were other factors such as increased
competition?
 It’s possible she really is an incompetent CEO.
 Can you generalize to all female CEOs?
Carly lost her job in Feb. 2005
Fundamental Attribution Error
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We overestimate the importance of personal tendencies
relative to situational factors in interpreting the behavior
of others.
I asked my husband to pick up some things at Trader
Joes when he went to exercise at Bally’s. I came home
and opened the refrigerator to find that he didn’t do it. I
got mad, assuming that he forgot or wasn’t listening (as
often happens when the TV is on). Turns out there was a
power failure and the shopping center was shut down
that evening.
Apple vs. Microsoft
Apple Computer, Inc. has failed to convince computer
users that its systems are better than those of its largest
competitor, Microsoft. How do we know? Just look at the
market share of each company’s respective operating
systems. Of the estimated 490 million personal
computers in use, 468 million are non-Mac PCs-the vast
majority of which use Windows. Mac OS, by comparison,
is used on a mere 22 million computers, about 4.5
percent of the total market share. Consumers have
stated their preference, and Windows is it.
(From page 161 in Asking the Right Questions 6th Edition)
A Conclusion and Reason
Conclusion: People prefer to use Windows
over Mac OS
Reason: Out of all of the personal
computers in use, only 22 million are Mac
OS.
Are there other possible causes?
Alternative Causes
Non-Mac PCs are easier to buy (more
alternative brands, more widely
available).
2. Non-Mac PCs may be cheaper.
3. More software runs on non-Macs
The consumer may prefer Mac but is
pushed toward buying a non-Mac PC.
Note: The newest PCs from Apple with Intel
processors now run Windows.
1.