The Skeptical Teacher

Musings of a science teacher & skeptic in an age of woo.

Archive for the ‘mathematics’ Category

More Media Fail and Silliness: Lunar Effect Babies

Posted by mattusmaximus on August 17, 2011

This week there’s been a story going around the media about a supposedly huge jump in births in a Sacramento hospital where “45 babies were delivered in 48 hours.”  Now that may or may not sound very unusual (it ends up it isn’t that strange – read on), but the really weird aspect of this is the claim made by the hospital officials with nary a skeptical thought:

“The human body is 80 percent water, after all. And, given that both menstruation and ovulation roughly follow a lunar cycle – occurring on a monthly basis – it doesn’t seem too far off to think that the moon could have a say in childbirth as well,” hospital officials said.

And, of course, the supposed mechanism for this “lunar effect”, as espoused by the hospital spokesman, is gravitational in nature:
According to the news release, the moon’s gravitational pull “can control a woman’s body” the same way the moon’s gravity controls tides.
*Cue spooky music…
Image courtesy of

First of all, the fact that 45 babies were born in 48 hours is not that significant.  Note the article states that there have been a total of 325,000 babies delivered at the hospital since 1937.  If you do the math, then this comes out to an average of about 12 babies per day – compared to the claim in the article (which basically averages out to about 22 or 23 babies in one day), this seems not very extraordinary because it shows that there was a weekend where the hospital had only double the average number of births!  100 times the average number of births would be statistically significant, but not 2 times the average.

Then there’s the stupid claim about the “lunar effect”.  Not only is this a bogus claim – click here to see why not – but it is also implausible from the standpoint of basic physics.  The hospital spokesman makes a common claim about the “lunar effect” being gravitational in nature, like the tidal effects on the Earth’s oceans.  However, if one takes a moment to work through the mathematics, this arguments falls apart pretty quickly.  For example, I perform the calculations for the tidal effects of the moon (whether it is full or not is irrelevant) on a person in my physics classes, and it ends up the tidal forces that act upon a person are stupendously small – about one-billionth the weight of a paperclip!  So whether or not you decide to wear a hat or use hair gel on any given day has more gravitational influence on you than does the tides from the moon!

That’s because the strength of the tidal forces that act on an object are proportional to the size of that object.  In the case of a large planet, like the Earth, the relative difference between gravity from one side of the planet to the other (this difference is the tide itself) is pretty big since the Earth is big.  But humans are so small on this size scale that the difference in gravity (tide) on us is miniscule.

So the next time you gaze upwards and see the full moon, appreciate it for all its beauty and wonder.  But don’t worry about it making you crazy; the failure of the media to accurately report science is a bigger threat of making you nuts ;)

Posted in astrology, mathematics, media woo, physics denial/woo | Tagged: , , , , , , , , , , , , , , , , , , , | 1 Comment »

Self-Tying Knot Trick from TAM9

Posted by mattusmaximus on July 18, 2011

Well, I’m back from The Amaz!ng Meeting 9 in Las Vegas, and I’m slowly but surely getting caught up on things.  I just wanted to take a moment to share with everyone a trick I showed off during my “Skepticism in the Classroom” lecture at TAM9.  In this video, I show how to use a simple nylon rope to perform a *seemingly* mathematically impossible feat: having the rope tie a knot in itself without releasing either end of the rope. I show this to my students as a lesson in skepticism and critical thinking, and it never ceases to catch their interest.

Can you figure out the trick? Stay tuned to my Youtube channel for the solution ;)

Posted in education, magic tricks, mathematics | Tagged: , , , , , , , , , , , , , , , , , , , , , , | 2 Comments »

The May 21st “Rapture”: When Crazy Religion Meets Crazy Numerology

Posted by mattusmaximus on May 19, 2011

I know that I’ve blogged a couple of times already (here and here) about the supposed impending “Rapture” coming up this coming Saturday, May 21st.  But while I’ve written there about how loony of an idea this whole Christ-is-returning-so-it’s-the-end-of-the-world is – mostly because there are so many failed doomsday predictions that were supposedly ironclad before they failed epically – one thing I haven’t yet done is to actually seriously analyze the claims made by the would-be prophet of this weekend’s Armageddon festivities, the good Rev. Harold Camping.

It’s Judgement Day!!!

My oh my, that Jesus is one fine lookin’ dude!  I wonder who does his hair? :)

In the following article, the rationale (such as it is) for Camping’s predictions is outlined.  Let’s take a look at the argument and then take it seriously just long enough to show the logical flaws within it, right before we piss ourselves with laughter…

End Times Math: The Equation That Predicts May 21 Judgment Day

The May 21 Judgment Day meme is the brainchild of an 89-year-old radio evangelist named Harold Camping. Using a mathematical system of his own creation to interpret obscure prophecies in the Bible, Camping originally predicted that Sept. 6, 1994 would be Judgment Day, or the day of the “Rapture” when Christian believers will ascend to heaven, leaving the rest of humanity to its deservedly dreary fate.

Hold on, right there.   Camping has made such a prediction before?  Yes, he did – he predicted the world would end almost 17 years ago… and the world is still here.  Also note this key phrase: “… Using a mathematical system of his own creation…” – what this basically means is that Camping has created a system of numerology which would allow him to manipulate the numbers of his calculation in such a fashion as to give him whatever result he wants.  In other words, using such a system, folks like Camping can’t fail… that is, until they actually fail, which is what happened to Camping on Sept. 7, 1994 when we were all still here.  But that’s the beauty of using slipshod and ad hoc mathematical systems such as Camping’s:  since they are essentially made up out of whole cloth with the express purpose of “never failing”, a missed prediction can easily be discounted when “corrections” to the calculations are magically uncovered after the fact.  This, like the thinking driving conspiracy theorizing, shows that such a system is clearly unfalsifiable: it is always right, even when it’s wrong.

The article continues:

… Here’s the gist of Camping’s calculation: He believes Christ was crucified on April 1, 33 A.D., exactly 722,500 days before May 21, 2011. That number, 722,500, is the square of 5 x 10 x 17. In Camping’s numerological system, 5 represents atonement, 10 means completeness, and seventeen means heaven. “Five times 10 times 17 is telling you a story,” Camping said on his Oakland-based talk show, Family Radio, last year. “It’s the story from the time Christ made payment for your sins until you’re completely saved.”

Okay, once again note that these numbers only make sense “in Camping’s numerological system” – which he made up.  What is the rationale which justifies Camping’s numerological system as being superior to that of other failed doomsday prophets (such as Nostradamus and those claiming the Mayan calendar portends The End on Dec. 21, 2012)?  And why does Camping settle on 722,500 days?  Why not 722,500 seconds, minutes, months, years, or centuries?  What is so special about days in Camping’s system which distinguishes them from any other unit of temporal measurement?  And, assuming there is some kind of reason (whatever that could be) for using days as units, why is it that you have to multiply and subsequently square 5, 10, and 17?  Why not simply add them up?  Or just multiply without squaring?  Or add them up and then square the result?  Why not raise the product of these numbers to the third power?  What is the rationale behind this calculation which explains why it could be considered trustworthy – other than, of course, the fact that it just happens to give a “prediction” of the world’s end, conveniently, during Camping’s lifetime?

And last, but not least, here’s a good question to ponder: if the Rapture is supposed to come on Saturday, May 21st, on which side of the International Date Line is that going to happen?  Will the Rapture follow the rotation of the Earth, seeing as how some parts of the planet will still be on Friday night time while other portions will be on early Saturday morning time?  Or is it supposed to just kind of go “poof!” all at once?  But if it does that, then it can’t all happen on the same day – and why doesn’t Camping take this into account in his calculations?  You can see the problem here.

Now that I’ve taken this stupidity seriously for a bit,  it is now time to treat it as the utter silliness that it most certainly is: I’m off to go get ready for the After Rapture Party & Looting ;)

Posted in doomsday, mathematics, religion | Tagged: , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 6 Comments »

Media Fail & Lotteries

Posted by mattusmaximus on January 22, 2011

This past December 17th, I saw a headline in my local paper which stunned me with the level of irresponsibility it displayed.  Back then the Powerball lottery was getting a lot of attention because the jackpot was up to a potential $25 million, and when such numbers start getting thrown around, people’s critical thinking skills go right out the window.  And it doesn’t help when the media joins the chorus of unreason…

First, there is the fallacy that when the jackpots are high, more people play because they “feel lucky that they’re going to win the BIG one!”  Of course, when more people play the lottery it actually decreases the odds that any specific person will win, yet this doesn’t stop the gullible from scarfing up the lottery tickets.

Then, there’s this horrible headline:

Wanna win Powerball? Try these numbers

For 13 years, a red ball with the number “20″ printed on it has been whirling around with its numerical counterparts in an enclosed Powerball kettle waiting to potentially make someone a millionaire. That No. 20 red ball has made its way out of the kettle 49 times, the most of any of the numbered balls. No. 20 also is the second most common number on the five white balls that are selected in each Powerball drawing as well, behind 26 and ahead of 32, 16 and 42, a Daily Herald analysis of the numbers shows. …

This headline and the leading paragraphs of the article play directly into the gambler’s fallacy of “lucky numbers” – in reality there are no more or less “lucky” numbers.  In fact, the past performance of the lottery is in no way, shape, or form a predictor of the next random drawing of numbers.  The article cited above actually does attempt to be at least marginally responsible by interviewing a mathematician, though their discussion is buried in the article…

… While some gamblers may see that information as an edge, mathematicians and oddsmakers say it’s all just luck.

“The numbers and the pingpong balls have no memory,” said Jeff Bergen, a mathematics professor at DePaul University. “So whether a given number has come up once or twice or 10 times or never, it is no more or less likely to come up today than any other number.” …

Exactly.  Unfortunately, the “news” article quickly followed up the math professor’s advice with some anecdotes from believers in these supposed lucky numbers.  So how did the Powerball drawing in question go?  Here were the results of the Dec. 18th Powerball drawing:

04-11-19-33-43 and 14 as the Powerball

And remember, the so-called “lucky numbers” referenced in the article were 16, 20, 26, 32, 42, and 20 for the Powerball.  Not a single one of these numbers appeared in the drawing – NOT… ONE. So much for “lucky numbers.”
So how should one win the lottery?  Simple: by not playing it at all.  To sum up the best way of dealing with this foolishness, I like this comment which appeared in response to the article:
You have much better chances of most things than of winning the lottery–getting struck by lightning, dying in a plane or car crash, etc. The odds are astronomically low of winning the big prize. Invest that money instead, and you’d end up with far more in the long-term, even with the low interest rates.
As for the “news” paper which so irresponsibly reported this article, I can only say one thing…

Posted in mathematics, media woo | Tagged: , , , , , , , , , , , , , , , , , , , , , , , | 5 Comments »

How to Always Pick a Winning Stock

Posted by mattusmaximus on December 21, 2010

This time of year, money is on a lot of people’s minds.  And especially with the crummy economy, it is REALLY on people’s minds.  Unfortunately, this is an environment which is ripe for various kinds of money-related scams.  In that spirit, I wanted to share with you all an excellent blog post by my skeptical colleague Phil Ferguson over at the Skeptic Money blog. It’s all about those schemes to “pick winning stocks” and whatnot; I can’t do it justice, so I’ll just pass along Phil’s post…

How To Pick Winning Stock Every Time – The Skeptics’ Way

Today I will show you how great stock pickers are able to find the winners – every time.  Now when you get a tip via a call or an e-mail from a broker you will know how they do it.  Now you can do it too.  If you use this same method you can guarantee a correct prediction on a stock.  With this system you can win every time.

I found this video from Darren Brown.  He calls it the system and I will stick with that name.  He uses it on horses but, I will tell you how to do it with stocks.  It is even better with stock because they can only go up or down.  It is so easy – it will blow your mind.  The same secrets apply to stocks as it does for horses.  Watch this video to see how it works.  Don’t skip ahead… YOU NEED to see how well this works. …

And yes, there IS an angle to this whole thing, but to see the angle read all the way through to the end of Phil’s post plus watch the accompanying videos.  However, for those of you who are a bit ADD, I’ll skip to the end:

… Someone had to win with each bet.  A stock picker can do the same thing.  They will call dozens, hundreds or even thousands of people.  They will tell half of the people that a given stock will go up and the other half will be told that the same stock will go down.  Those that lose never get called again.  The winners are called again and get a new stock tip.  So with just 16 people to start with a stock picker can get 4 in a row for one lucky person.  Now that person will do just about anything.  Even borrow money from friends.  They may or may not make money.  It does not matter to the broker.  Each time you buy or sell a stock, you make will make the broker money.

Now, when someone calls you with a hot stock tip, you will know what to do – RUN!

Posted in economics, mathematics | Tagged: , , , , , , , , , , , , , , , , , , , , , , , , , | Leave a Comment »

Prayer, Miracles, and Damned Statistics

Posted by mattusmaximus on April 7, 2010

We’ve all heard the line: There’s lies, damned lies, and then there’s statistics. The implication is that people can use statistics to deceive themselves and others.  But the opposite is also true: people often deceive themselves due to a stark ignorance of numbers & statistics (often referred to as innumeracy).

For example, at this time of year, at least in Christian circles, there is a lot of talk going around about prayer and miracles – usually in the guise of stories about supposedly “miraculous” healing.  And the media loves to give air time to these kind of anecdotal stories with nary a whiff of skepticism.  However, to its credit, ABC News did a segment recently with Elizabeth Vargas where she gave a fair amount of face-time to skeptic Michael Shermer.  Here are some excerpts from Shermer’s account of the interview at the really groovy SkeptiBlog…

Would I Ever Pray for a Miracle?

I really like how Shermer goes into the issue of large number statistics, confirmation bias, and believers counting the “miraculous hits” while discounting the enormous number of inevitable misses…

Read the rest of this entry »

Posted in mathematics, religion | Tagged: , , , , , , , , , , , , , , , , , , , , , , , , , | 2 Comments »

“Toyota Terror” and Media Scare-Mongering

Posted by mattusmaximus on February 15, 2010

Yes, we’ve all been hearing in the media lately about how Toyota is issuing major recalls for many of its most popular vehicles, such as the Camry & Prius.  The problems, we are told, range from sticky accelerator pedals to brakes that don’t function properly.  In addition, the media have made a really big point of noting that the accelerator problem has likely led to a whopping 19 deaths over the last decade!!!  ZOMG!!!11!1

Errr… that’s it?  19 deaths in a decade?  Really, that’s the big news?  Not to sound cold & heartless, but this seems so like the making of a molehill into a mountain in an effort by the media to keep a story going, when it’s obviously well past its “sell by” date.  To get a little perspective, let’s take a look at this responsible article by NPR on this issue…

Most Auto Accidents Caused By Drivers, Not Defects

Driving a Toyota may feel pretty risky these days, given all the scary stories about sudden acceleration, failing brakes and recalled vehicles. But that feeling has a lot more to do with emotion than statistics, experts say. That’s because defective vehicles are almost never the cause of serious crashes.

“The whole history of U.S. traffic safety in the U.S. has been one focusing on the vehicle, one of the least important factors,” says Leonard Evans, a physicist who worked for General Motors for three decades and wrote the book Traffic Safety.

To Err Is Human

Studies show that the vehicle itself is the sole cause of an accident only about 2 percent of the time. Drivers, on the other hand, are wholly to blame more than half the time and partly to blame more 90 percent of the time.

A look at data on Toyotas from the National Highway Traffic Safety Administration confirms this pattern. The data show that in the decade ending in 2008, about 22,000 people were killed in vehicles made by Toyota or Lexus, Evans says. “All these people were killed because of factors that had absolutely nothing to do with any vehicle defect,” he says.

During that same period it’s possible, though not yet certain, that accelerator problems in Toyotas played a role in an additional 19 deaths, or about two each year, Evans says. And even if an accelerator does stick, drivers should be able to prevent most crashes by simply stepping on the brakes, Evans says. “The weakest brakes are stronger than the strongest engine,” he says.

Read the rest of this entry »

Posted in mathematics, media woo | Tagged: , , , , , , , , , , , , , , , , , , , , , , , , | 2 Comments »

Why So Much of Polling is B.S. — F**k You, Frank!

Posted by mattusmaximus on October 3, 2009

“The numbers don’t lie” goes an oft-quoted saying… and that’s true, for the most part.  Numbers don’t lie, but what does lie is the people who are reporting the numbers.  The recent brouhaha over health care reform in the United States has brought this fact about numbers & statistics into stark relief of late.  Most people, when they read a poll, don’t really think about the numbers all that much, or they are too innumerate to really understand what they’re reading – which is how so many are easily manipulated.  And oftentimes the polls are self-contradictory.

For example, look at this recent article – which is, refreshingly, a good example of critical thinking in the modern media – concerning the question of polling public opinion on health care reform…

Health care polls leave pols dizzy

Legislators hoping to learn what their constituents think about the issue — and how to vote to keep them happy — face a dizzying deluge of hard-to-reconcile data, some of which suggests that voters are more than a little confused, as well.

What to make of it, for example, when one poll finds that 63 percent think “death panels” are a “distortion” or “scare tactic,” and only 30 percent think the issue is “legitimate,” while another finds that 41 percent believe that people would die because “government panels” would prevent them from getting the treatment they needed?

Or when one survey finds that 55 percent of Americans support the public option, while another says 79 percent favor one — but also notes that only 37 percent people surveyed actually knew what “public option” meant?

And because there is such ambiguity in these polls, those with an agenda can usually cherry-pick whatever data they want to make a case for their particular argument.  Even changing the wording of a particular question just slightly can have a huge impact…

Read the rest of this entry »

Posted in mathematics, media woo, politics | Tagged: , , , , , , , , , , , , , , , , , , , , | 5 Comments »

Las Vegas: A Town Based on Bad Math & Gullibility

Posted by mattusmaximus on July 15, 2009

During my recent trip to Las Vegas for TAM7, as with all my previous trips to “Sin City”, I noticed the large number of people gambling.  Now there is a certain social aspect to gambling, but a lot of people play these games of chance hoping that they’ll win it big.  They literally believe that, through some lucky charm or prayer, that they’ll hit the jackpot, and that’s exactly what the casinos want them to believe…


Of course, the casinos in Vegas are banking on a combination of people’s lack of critical thinking & skepticism, innumeracy (misunderstanding of math), susceptibility to the gambler’s fallacy, and basic gullibility – and based upon what I’ve seen, the casinos have been quite successful at cashing in on all of these things.

That’s because in addition to knowing basic human nature, the casinos also know the mathematical odds. They don’t say “the house always wins” for nothing, folks.  Even if someone occasionally wins it big (which will eventually happen by the law of large numbers, just as when someone wins the lottery), there are way more people who are losing money.  In the end, these casinos make much more money than they pay out.

Ironically, I saw the following slot machine sign while in Vegas…


In order to make this sign a more accurate reflection of reality, one of the O’s should be crossed out, because chances are that if you’re playing these games you’ll end up a loser.  So, statistically speaking, how does one win in Vegas (without cheating)?  The answer is simple, folks: you don’t play the game :)

Posted in mathematics, psychology | Tagged: , , , , , , , , , , , , , , , , , | 2 Comments »

Damn Lies & Statistics: Who’s Counting?

Posted by mattusmaximus on April 18, 2009

In the United States, tax day (April 15th) has just passed, and this year we had a rather interesting series of anti-tax events organized by Fox News called “Tea Parties”. The organizers of these events were, at one point, estimating perhaps millions of people in attendance.

fox news tea party

To me, the interesting thing about events like this is the numbers of people that are reported to have attended. In an attempt to apply a version of the argument from popularity, organizers of such events will tend to over-estimate attendance while those in opposition to such events usually try to downplay those same numbers.

Sometimes, when we see polls or statistics being reported in the media or by some interest group, the numbers are presented to us as what Dr. Joel Best (author of “Damned Lies & Statistics”) refers to as “little nuggets of truth”. However, a deeper analysis of such reports often presents a very different picture.

Read the rest of this entry »

Posted in mathematics, media woo, politics | Tagged: , , , , , , , , , , , , , , , , , , | 3 Comments »


Get every new post delivered to your Inbox.

Join 102 other followers