Combating Data Manipulation VII: Patterns and Randomness

What is “randomness”?

Something is considered “random” when it seemingly has no pattern and is unpredictable, meaning that if you rerun the same process multiple times, you will get different results even if everything remains the same.

How do we know if something is “random”?

Humans are notoriously bad at identifying randomness; in fact, humans consistently seem to find patterns even in perfectly random processes.  It is how the “monkey-flower” got its name (see https://www.google.com/search?q=monkey+flower&client=firefox-a&hs=TU3&rls=org.mozilla:en-US:official&channel=fflb&biw=1280&bih=672&tbm=isch&imgil=qRiAyo3nhnEjRM%253A%253Bhttps%253A%252F%252Fencrypted-tbn0.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9GcSUFN1KRHJ26dYym983EQ5YCFRE2XBRnDPJBeIWF4RgS5cq2suj%253B720%253B720%253BrEmPXOY-8aw1hM%253Bhttp%25253A%25252F%25252Fwww.flowershopnetwork.com%25252Fblog%25252Fflowers-imitating-monkeys%25252F&source=iu&usg=__CWHSIJrI2lr47xyX_7QdptaLUQ8%3D&sa=X&ei=VBSGU-G_HNCBqgbY1YLYAQ&ved=0CKsBEP4dMAw#channel=fflb&q=monkey%20face%20flower&revid=553318842&rls=org.mozilla%3Aen-US%3Aofficial&tbm=isch&imgdii=_) and why superstitions exist.  When a student does really well on two tests in a row wearing the same shoes, instead of attributing it to studying or pure random chance, they carefully put the “lucky shoes” away in their closet until their next test.  When a Fortune 500 company loses a lot of money over a certain period of time, instead of suggesting that random processes in the market could have caused it, people fire the CEO because there needs to be a pattern and a reason for each event.

People are also pretty bad at identifying random processes when they are supposed to be random.  Leonard Mlodinow in his book The Drunkard’s Walk tells a story of the first few generations of iPods that Apple developed; they initially created the “shuffle” function to be purely random, as it is supposed to be.  However, purely random processes can repeat themselves, and Apple began to hear complaints that the “shuffle” function was not random because the same song would play back to back, or the same artist would play for three songs in a row.  Apple actually had to make “shuffle” less random so people would believe that it is more random.

There are a lot of mathematical ways to determine whether a process is truly “random,” but the simplest way is to just entertain the idea that not everything follows a pattern.  The process of finding great actors, hiring CEO’s, getting accepted to schools all are affected somewhat by random processes.  Who knows, maybe if big TV shows like Modern Family or movies that make a lot of money like Avatar or Frozen had been aired 10 years later or 10 years earlier or even if we had rewound time and done it all again, they wouldn’t have done as well.

For those still interested in the idea of “randomness,” I put a youtube video of Leonard Mlodinow giving a talk in the works cited section; you should check it out!

Works Cited

http://www.scientificamerican.com/article/how-randomness-rules-our-world/?page=1

http://en.wikipedia.org/wiki/Randomness#cite_note-1

http://plato.stanford.edu/entries/chance-randomness/#2.1.1

http://www.math.tamu.edu/~Michael.Pilant/math614/chaos_vs_random.pdf

http://stat.math.uregina.ca/~kozdron/Teaching/Regina/862Winter06/Handouts/revised_lecture1.pdf

http://www.scientificamerican.com/article/patternicity-finding-meaningful-patterns/?page=2

Leonard Mlodinow, The Drunkard’s Walk: How Randomness Rules Our Lives

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Alcohol Breakdown in the Body

What is the alcohol that we drink?

In chemistry, “alcohol” can describe any compound that contains a hydroxyl group (an oxygen bonded to a hydrogen, or -OH).  When we talk about drinking alcohol, however, we mostly refer to ethanol, which is CH3CH2OH, or a 2-carbon chain attached to a hydroxyl group.

How do we metabolize alcohol?

When people drink alcohol, their bodies break it down in three stages.  The first stage breaks ethanol into acetaldehyde, which is much more toxic than ethanol and is responsible for a sick feeling after drinking a lot of alcohol.  This happens using an enzyme, which is a protein that helps speed up reactions, called alcohol dehydrogenase.  The second stage breaks the acetaldehyde into acetic acid, and then the third stage eventually breaks that down into carbon dioxide and water, which is then eliminated from the body.

Why can some people drink more alcohol than others?

The enzyme alcohol dehydrogenase has many different forms, and certain forms are more efficient than others.  The people who have more efficient forms of this enzyme tend to feel sick from alcohol quicker, because their body very rapidly converts ethanol into toxic acetaldehyde.  Some evidence that suggests the levels of this enzyme decrease as people age, which could lengthen the period of intoxication.

Why is it bad to drink methanol?

Methanol, an alcohol form that contains only one carbon with an -OH group, CH3OH, is toxic and can cause blindness.  This is because, when methanol is broken down by alcohol dehydrogenase, it breaks down into formaldehyde and then formic acid.  Formic acid can harm the optic nerve, cause blindness, and also impairs the ability of mitochondria to function.  Some scientists suggest that the cure to methanol poisoning, if caught in time, may actually be to ingest ethanol, although it is still very dangerous.  This is because the breakdown of methanol is much slower than ethanol, so if both are ingested alcohol dehydrogenase will break down ethanol first, allowing the body to excrete methanol without breaking it down.

Why shouldn’t you drink alcohol on an empty stomach?

Ethanol is a small molecule, allowing it to easily move through the walls of the stomach and the small intestine, but mostly through the small intestine because there is so much surface area in the small intestine that a lot more ethanol can diffuse there.  When there is food in the stomach, the pyloric sphincter (the muscle that forms the entrance of the small intestine from the stomach and can open and close to allow food into the small intestine) is closed to allow the food in the stomach to digest a bit.  This prevents too much ethanol from going into the bloodstream from the walls of the small intestine because it can’t get into the small intestine.  This delays intoxication because the alcohol cannot get into the blood.  If that sphincter is open, however, lots of alcohol can get into the blood all at once.

Why does alcohol make people feel warm?

Once the alcohol gets into the bloodstream, it causes the blood vessels to widen (also known as vasodilation), which allows a lot of heat to rise to the surface of the skin and dissipate into the air.  This makes people feel really warm, because the heat goes to their skin, but actually it causes a net loss of body heat.

Why do people say that men can drink more than women and reach the same level of intoxication?

While this is definitely a generalization and is different among individuals, in general this can be true.  Ethanol has the very polar -OH group (it is polar because the electrons move towards the electronegative oxygen) and therefore cannot get into completely fatty, nonpolar tissue.  Since women tend to have a higher concentration of fatty tissue than men do, the same amount of alcohol is able to diffuse into fewer cells in women than men, meaning there is more alcohol per cell in women than men.  This can cause women to become intoxicated faster than men.

Why do people say alcohol causes weight gain?

Typically when someone ingests food or drink, some part of that is stored as fat that can be used later if the body needs it.  The rest of the calories from the food or drink are used to sustain the body.  However, the energy from ethanol cannot be stored in the body, so the body uses the energy from ethanol to perform typical functions, giving energy to muscles and the brain to sustain life.  However, since ethanol is being used as energy, any other food or drink ingested that would otherwise be used has to be stored.  This can probably only cause weight gain in large quantities however.

Why do people drink coffee to cure hangovers?

The headache in hangovers can be caused by vasodilation in the head, which is the widening of blood vessels in the head.  Caffeine actually is a vasoconstrictor, meaning it constricts blood vessels, so coffee or tea can reverse the effects of certain hangover headaches. They are not actually overall cures for hangovers, however.

Works Cited

McGee, Harold; On Food and Cooking: The Science and Lore of the Kitchen: Scribner, 2004, 713-720.

Smart, Lesley; Alcohol and Human Health: Oxford University Press, Oxford, 2007.

Elmhurst College, “Alcohol Metabolism Effects,” http://www.elmhurst.edu/~chm/vchembook/642alcoholmet.html.

Campbell, Mary K. and Farrell, Shawn O., Biochemistry: 6th Edition, Thomson Higher Education, 2009.

PubChem Compound, National Center for Biotechnology Information, http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=176#x27.

DNA Learning Center, Cold Spring Harbor Laboratory, http://www.dnalc.org/view/485-GABA-Neurotransmitter.html.

National Institutes of Health and National Institute on Alcohol Abuse and Alcoholism, Information about Alcohol, http://science.education.nih.gov/supplements/nih3/alcohol/guide/info-alcohol.htm.

Montoliu, C., Valles, S., Renau-Piqueras, J., Guerri, C.  Ethanol-Induced Oxygen Radical Formation and Lipid Peroxidation in Rat Brain: Effect of Chronic Alcohol Consumption.  Journal of Neurochemistry.  1994, Vol. 63, Issue 5, 1855-1862.

Lobo, V., Patil, A., Phatak, A., Chandra, N. Free radicals, antioxidants and functional foods: Impact on human health.  Pharmacognosy Review.  2010, 4(8): 118-126.

Zakhari, S., Overview: How is Alcohol Metabolized by the Body?  NIH: NIAAA Publications, http://pubs.niaaa.nih.gov/publications/arh294/245-255.pdf.

PubChem Compound, National Center for Biotechnology Information, http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=119.

PubChem Compound, National Center for Biotechnology Information, http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=33032.

Brent, Jeffrey; McMartin, Kenneth; Phillips, Scott; Aaron, Cynthia; Kulig, Ken. Fomepizole for the treatment of methanol poisoning. The New England Journal of Medicine. 2001, 344, 424-429.

Koop, Dennis R., Alcohol Metabolism’s Damaging Effects on the Cell: A Focus on Reactive Oxygen Generation by the Enzyme Cytochrome P450 2E1, NIH: NIAAA Publications, Volume 29, Number 4, 2006, http://pubs.niaaa.nih.gov/publications/arh294/274-280.pdf

Dekker, Anthony, What are the effects of alcohol on the brain?  Scientific American, July 26, 1999, http://www.scientificamerican.com/article.cfm?id=what-are-the-effects-of-a.

What is happening to the climate: Vostok Ice Core Data

Many researchers in 1999 published a paper examining ice core data from the Vostok lake, which allows us to see 400,000 years into the past (see the previous post about how ice core stratigraphy works).

Here is one graph from their paper (http://www.nature.com/nature/journal/v399/n6735/full/399429a0.html) representing their results:

The graph is a little tough to read, but if you can see on the sides there are 5 lines, representing CO2, temperature, CH4 (methane), oxygen-18 isotope (for explanation see the previous post about ice core stratigraphy) and insolation, respectively.

One of the important parts of this graph is how the greenhouse gases and temperature are related; the graphs seem to be very, very similar, further suggesting a relationship between them.

A very noticeable part of this graph, though, is its cyclical nature.  Temperature and greenhouse gas concentrations fluctuate on a cycle, which could fuel the argument from climate change skeptics that climate change is just a natural cycle.

But what cause these cycles?  Well, for the most part they are caused by different tilting and spinning of the earth.  First, the actual tilt of the Earth’s axis changes in a cyclic nature and this influences the temperature of the Earth.  Second, the radius of the orbit around the Sun also changes, affecting temperature.  Third, precession, which is the “wobbling” of the Earth around its axis, also affects temperature.

Antarctic Glaciers (via Wikimedia Commons) have an extension of this graph showing new data, and it is clear that the current levels of carbon dioxide far exceed that of the natural cycles in the past.

https://i2.wp.com/cdn.antarcticglaciers.org/wp-content/uploads/2012/07/Vostok_420ky_4curves_insolation_to_2004.jpg

This cycle is known as the Milankovitch cycle, and it lasts about 100,000 years.  However, we should be currently in the cooling part of the cycle, but the levels of carbon dioxide put in by humans have caused us to deviate from this cycle.

Global Mean Temperature 150,000 years

This graph is from the NOAA and shows where we should be in the cycle and how different the last cycle was from our current position.  (For more graphs and visuals, see http://ossfoundation.us/projects/environment/global-warming/natural-cycle).

So far, current data suggests that climate change is anthropogenic and is a problem that we are currently facing.

Look out for more posts about the evidence for anthropogenic global warming!
Works Cited

Combating Data Manipulation VI: Conditional Probability

What is “conditional probability”?

Conditional probability is the probability that some A will occur given B that has already occurred.

What is its significance?

One of the applications of conditional probability is in law; it is part of a concept known as the Prosecutor’s Fallacy.  This rests on the incorrect assumption that the probability that A will occur given B is the same as the probability that B will occur given A.  The first, and most common, example is the Sally Clark case.

Sally Clark Case

Sally Clark had one son in 1996 who died fairly quickly after his birth.  Again, she had a second son and he died quickly after his birth.  She said that they both died of SIDS (Sudden Infant Death Syndrome), but she was still arrested for killing her two sons.  During her trial, a statistician declared that the probability of a child dying of SIDS is 1 in 8500, and therefore the probability of two children dying of SIDS is 1 in 73 million ((1/8500)^2).  This seems fairly persuasive, and in fact the jury thought so too and convicted her.

But, the statistician ignored conditional probability: it turns out, the probability that a second child will die of SIDS if the first one has already died of SIDS increases substantially.  Additionally, the probability of a child dying of SIDS if the child is male is also much higher.

Secondly, the jury should have weighed the two possibilities: that of both children dying of SIDS and that of Sally Clark killing both her sons.  It turns out that the probability that Sally Clark killed both her sons is much, much lower than the probability that they both died of SIDS.  The jury, the lawyer, and the statistician did not consider these when arguing the case.

OJ Simpson Case

OJ Simpson was on trial, suspected of killing his ex-wife.  There was lots of evidence against him, but the defense argued that because Simpson abused his wife, it was highly unlikely that he would kill her (the statistic was 1 in 2500 abusers kill their significant others).  Therefore, to the jury, it seemed like OJ Simpson was likely to be innocent.

However, the pertinent statistic at this trial was not the one presented.  As Leonard Mlodinow puts it, “The relevant number is not the probability that a man who batters his wife will go on to kill her (1 in 2,500) but rather the probability that a battered wife who was murdered was murdered by her abuser” (120).  And, the relevant probability was about 9 in 10 abused women who were killed were killed by their abusers.  Therefore, statistics was actually in favor of the prosecution, not the defense.

When thinking about probability, the lesson to take from these two cases is that it is very important to think about the relevant probability.

The next post in this series will discuss patterns and randomness!

Works Cited

http://www.stat.yale.edu/Courses/1997-98/101/condprob.htm

http://www.statisticalconsultants.co.nz/weeklyfeatures/WF18.html

Leonard Mlodinow, The Drunkard’s Walk

http://understandinguncertainty.org/node/545

http://www.conceptstew.co.uk/PAGES/prosecutors_fallacy.html

http://faculty.mc3.edu/cvaughen/probability/prosecutorsfallacy.pdf