Transcript BIAS

Notes
SPI 0807.Inq.5
Bias and Error
Science
Bias and Error in Science
Bias: this means you are
prejudiced towards or against
Instructions
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top-menu
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results
of your
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Science
about this
obtaining
accurate results
advanceisthrough
presentation.
so bias should NEVER be allowed to influence
your experimental results!
Bias Is Bad!
Bias
Bias
Notes
SPI 0807.Inq.5
Bias and Error
Science
Bias in Science Experiments
Example: Imagine that you doing an experiment to determine
which NFL football quarterback can throw a football the furthest.
Your favorite football team is the Tennessee Titans, so you are
disappointed with your data when you notice that the Titans'
quarterback's throwing distance is not the furthest. Yet because this
is your favorite quarterback, you change the data so that this
quarterback appears to throw the furthest.
This is BIAS, and it should NEVER be allowed in science.
Notes
SPI 0807.Inq.5
Bias and Error
Science
Example:
Bubba loves to eat french fries with lots of extra salt.
He conducts an experiment to determine how much
better french fries taste with lots of extra salt.
Identify the bias or error in this situation
ANSWER: Because Bubba likes extra salt on his fries, he
wrongly assumes that everyone else will like extra salt too.
He is biased toward salt, so his results will contain errors.
BIAS should NEVER be allowed in science experiments!
Notes
SPI 0807.Inq.5
Bias and Error
Science
Bias in Science
Two students who love Justin Bieber’s music do an
experiment to measure how long people have to hear one of
Justin’s songs before they too fall in love with his music.
Question: Which choice below most likely will occur?
(Just write the correct letter)
A) Bias
B) Fraud and Waste C) Song and Dance
Answer: These two students are biased towards
Justin Beiber, so their results will probably be biased and
wrong too
BIAS should NEVER be allowed in science experiments!
Notes
SPI 0807.Inq.5
Bias and Error
Science
Solutions to Bias in Science
 Humans are imperfect, so bias happens both intentionally
and unintentionally
Ways to Reduce and/or Eliminate Bias
 Be aware that bias can and does happen
 Strive to recognize it, and eliminate it from your
experiments.
 Follow the steps and principles of the scientific method
 Make sure that others rigorously review your work
looking for bias
SPI 0807.Inq.5
Famous
Examples
of
Bias
in
Science
Notes
Science
Bias and Error
Thomas Edison and Direct Current Electricity
Thomas Edison
Famous Examples
of Bias in Science
Edison
Tesla
DC vs AC (Edison vs Tesla: 1880s)
Edison promoted direct current electricity (DC), but
Nikola Tesla promoted alternating current (AC).
Bias:
Experiments had clearly demonstrated that alternating
current was more practical and less expensive.
Yet Edison was biased for DC and refused to yield.
Nearly all electricity generated today is AC
SPI 0807.Inq.5
Famous
Examples
of
Bias
in
Science
Notes
Science
Bias and Error
Dr. Hwang Wook Suk and Cloning Technology
Dr. Hwang Woo Suk
Famous Examples
of Bias in Science
Cloning Technology (Dr. Hwang Woo Suk)
In 1999 he claimed to have cloned a cow.
In 2004 he claimed to have cloned human stem cells.
In 2005 he claimed to have cloned a dog.
Bias:
He had fabricated and/or deleted experimental data.
In 2006 he was dismissed from Seoul National
University, and he was indicted for fraud,
embezzlement, and violations of bioethics laws.
Notes
SPI 0807.Inq.5
Bias and Error
Science
Errors in Science
Avoid Mistakes:
 One small error can result in all your experimental data
being wrong
 So scientists work very hard to avoid making mistakes
Peer Review:
 One key way scientists deal with this issue is by having
other scientists review their work to check for mistakes
 This very common practice is called peer review
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SPI 0807.Inq.5
Bias and Error
Science
Errors in Science
To Avoid Mistakes:
 Make sure you are following the steps of the scientific
method
 Make sure you have only one independent variable at a
time
 Make sure you correctly identify your dependent
variables
 Make sure you include valid control experiments
 Make sure you record in detail every step of your
experiment
 Ask someone else to review all your work (peer review)
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SPI 0807.Inq.5
Bias and Error
Science
Famous Errors in Science
Mars Climate Orbiter:
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SPI 0807.Inq.5
Bias and Error
Science
Famous Errors in Science
Mars Climate Orbiter:
launched by NASA in December 1998, this robotic
spacecraft was designed to study weather on Mars.
Expensive Mistake:
A design team used standard units (pounds- seconds)
while a different design team used metric units
(newtons- seconds). So instead of orbiting Mars, the
spacecraft crashed to the surface of the red planet.
Cost of this mistake: $327 million dollars
Notes
SPI 0807.Inq.5
Bias and Error
Science
Famous Bias and Errors in Science
Canals on Mars
Astronomer: Percival Lowell
Notes
Famous
SPI 0807.Inq.5
BiasBias
and
Errors
and Error
Science
in Science
From 1894 to 1908 Percival studied the planet
Mars with a large telescope.
Notes
Famous
SPI 0807.Inq.5
BiasBias
and
Errors
and Error
Science
in Science
Percival was fascinated about the possibility of
intelligent life on Mars .
He was biased about this.
He observed hazy images of the surface of Mars
His bias lead him to make significant
errors about what he saw.
He wrongly concluded that the features on Mars
were canals built by extraterrestrials (Martians)
Later observations by others confirmed that there
are no canals or signs of intelligent Martian life.