twisted statistics

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Twisted Statistics Kevin A. Barnes April 23, 2008

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This session examining some of the ways that statistics can be used to misrepresent information or mislead audiences was presented at Marquette University on April 23, 2008.

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Page 1: Twisted Statistics

Twisted Statistics!

!!

Kevin A. Barnes!April 23, 2008!

Page 2: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Tonight on “Twisted Statistics”!

! Introduction!! Part I: When statistics go bad!! Part II: Fun with Charts & Graphs!! Part III: The Ten Commandments of Data

Collection!! Part IV: Online Resources!! Questions and Conclusion!

Page 3: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Statistics or Sadistics?!

“Statistics will one day be as necessary for efficient citizenship as the ability to read and write.” -- H.G. Wells!

“There are three kinds of lies: lies, damn lies, and statistics.” -- attributed (by different sources) to Mark Twain or Benjamin Disraeli!

!

Page 4: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Types of Statistics!

! Accurate!! Inaccurate (unintentionally misleading)!! Inaccurate (intentionally misleading)!

Page 5: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Tonight on “Twisted Statistics”!

! Introduction!! Part I: When statistics go bad!! Part II: Fun with Charts & Graphs!! Part III: The Ten Commandments of Data

Collection!! Part IV: Online Resources!! Questions and Conclusion!

Page 6: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Definitions!

! Eighty-four percent of Europeans have mixed feelings about the United States.!

Page 7: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Hyperaccuracy!

! The Native American mounds in Wisconsin are 12,003 years old.!

Page 8: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Measurement by Proxy!

! Almost everyone loves Mocha-Cola. Less than 1% of Mocha-Cola drinkers have asked for their money back.!

Page 9: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

It Sounds Shocking, So …!

! Forty percent of all employee sick days occur on a Monday or a Friday.!

Page 10: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Jumping to Conclusions!

! Claim: Several individual countries have improved their infant mortality rates more than U.S. since 1980.!

! Conclusion Offered: The state of health care in the U.S. is inadequate.!

Page 11: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

In Comparison To …!

! Crystal Meth use among U.S. urban teenagers is 20% lower.!

Page 12: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Deduction is not Induction!

! Observation: Sally, Betty and Joanne are women.!

! Observation: Sally, Betty and Joanne love Harrison Ford.!

! Conclusion: All women love Harrison Ford.!

Page 13: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Plain Old Urban Legends!

! Humans use only 10% of their brain.!

Page 14: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Other Things to Watch …!

! Make sure you’re getting the whole story!

! Consider the credibility of the original data source!

! Do a basic logic check - do the statistics make sense, or does something seem out-of-place?!

! In percentages, is the base too small!

Page 15: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Tonight on “Twisted Statistics”!

! Introduction!! Part I: When statistics go bad!! Part II: Fun with Charts & Graphs!! Part III: The Ten Commandments of Data

Collection!! Part IV: Online Resources!! Questions and Conclusion!

Page 16: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Fun with Charts & Graphs!

From How to Lie with Statistics, Darrell Huff, 1954

Page 17: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

More Fun with Charts & Graphs!

From How to Lie with Statistics, Darrell Huff, 1954

Page 18: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Tonight on “Twisted Statistics”!

! Introduction!! Part I: When statistics go bad!! Part II: Fun with Charts & Graphs!! Part III: The Ten Commandments of Data

Collection!! Part IV: Online Resources!! Questions and Conclusion!

Page 19: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

The Ten Commandments of Data Collection!1.  When you begin thinking about a

research question, begin thinking about the type of data you need to collect to answer that question.!

Page 20: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

The Ten Commandments of Data Collection!2.  As you think about the type of data you

will be collecting, think about where you will be getting that data.!

Page 21: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

The Ten Commandments of Data Collection!3.  Make sure the data forms you use are

clear and easy to use.!

Page 22: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

The Ten Commandments of Data Collection!4.  Always make a duplicate copy of the

data file and keep it in a separate location.!

Page 23: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

The Ten Commandments of Data Collection!5.  Do not rely on other people to collect or

transfer your data unless you have trained them.!

Page 24: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

The Ten Commandments of Data Collection!6.  Plan a detailed schedule of where and

when you will be collecting your data.!

Page 25: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

The Ten Commandments of Data Collection!7.  As soon as possible, cultivate sources

for your subject pool.!

Page 26: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

The Ten Commandments of Data Collection!8.  Try to follow up with subjects who

missed their testing session or interview.!

Page 27: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

The Ten Commandments of Data Collection!9.  Never discard the original data, such as

test booklets, interview notes, etc.!

Page 28: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

The Ten Commandments of Data Collection!10. Follow the previous 9 commandments!!

“Ten Commandments of Data Collection” courtesy of Neil J. Salkind, University of Kansas

Page 29: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Tonight on “Twisted Statistics”!

! Introduction!! Part I: When statistics go bad!! Part II: Fun with Charts & Graphs!! Part III: The Ten Commandments of Data

Collection!! Part IV: Online Resources!! Questions and Conclusion!

Page 30: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Online Resources!

! http://calculators.stat.ucla.edu/ => Almost every type of statistical calculator you could ever need!

! http://www.davidmlane.com/hyperstat/ => Hyperstat Online - An Introductory Statistics Guide and Online Tutorial!

Page 31: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Online Data Sources!

! http://www.census.gov/main/www/access.html => US Census Data!

! http://www.lib.umich.edu/govdocs/stats.html => The University of Michigan Statistical Resources (statistical data on dozens of topics from accidents to world development)!

Page 32: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Tonight on “Twisted Statistics”!

! Introduction!! Part I: When statistics go bad!! Part II: Fun with Charts & Graphs!! Part III: The Ten Commandments of Data

Collection!! Part IV: Online Resources!! Questions and Conclusion!

Page 33: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Questions?!

! What is the average air speed velocity of an unladen swallow?!

Page 34: Twisted Statistics

© Copyright 2008. Kevin A. Barnes. All Rights Reserved!

Contact Information!

! Email: [email protected]!

! Download a PDF of this presentation at: www.kevinabarnes.com/downloads/mu/!