If you’re finding my weekly brain teaser too low stakes, try this one, win a million bucks!

There are 11 ways of expressing the number 100 as a number and fraction using the nine digits once each.
Example:

91+ (5823/647) = 100

The challenge is to find some of the other 10 ways.

Hint: In 9 of them, that first number is above 80.  In one of them, it’s less than 10.

I’ve mentioned before on this blog that I get annoyed when people link A to B and B to C and then proceed to assume that the relationship between A and C is just the average/sum/etc of the first two.  In pure mathematics, the technical term for this is transitivity and it tends to be pretty valid.

I learned recently that there is actually a term for this when applied to epidemiology research: teleoanalysis.  Developed in the realm of public health, it’s defined as

the synthesis of different categories of evidence to obtain a quantitative general summary of (a) the relation between a cause of a disease and the risk of the disease and (b) the extent to which the disease can be prevented. 

It has also been criticized, in large part because it was invented to help support pre-existing assumptions.  Both papers I linked to reference the “does cutting back on saturated fat actually prevent heart disease” controversy as an example.

I was thinking of this recently when reader Dubbahdee sent me this article about bicycle helmet laws.  The issue follows the same formula as above:

A. Bicycle helmets protect cyclists
B. Mandatory helmet laws increase the number of cyclists who wear helmets

Therefore:

C. Bicycle helmet laws save lives

What’s interesting is it appears this is not the case.  The paper’s authors suggest that increased helmet laws decrease bike ridership, and apparently having lots of bicyclists in an area makes it safer for cyclists in general.  Also, helmet laws seem to potentially inoculate lawmakers against making any bigger changes…the sort that actually help cyclist safety (infrastructure building, etc).

I thought this was interesting because it’s absolutely proven that you as an individual should wear a helmet, but the conclusions drawn from that weren’t valid.  Someone out there guaranteed that these helmet laws would save x number of lives, and they were wrong.

I had a nasty migraine last night that kept me up for most of the night, and I’m not sure I have a real post in me.

In lieu of that, I have a linguistic issue I’d like to get off my chest: Misnomer does not mean “error” or “misconception”…it refers to an error in naming.

I’m sure my very smart and wonderful readers know this, but 3 times in the past two weeks I’ve heard people make this error.  If you’re going to try to use big/unusual words, please use them accurately.  Oh, and that also goes for phrases in Latin.  Saying part of your argument in Latin doesn’t make you right.

Good morning!  It’s hard to find fun links this week.  Why?  Because George @#&$@* Martin wrecked my life.  Game of Thrones may land me in therapy.  I knew about the red wedding, but really George Martin, really?  Your life goal is to make your readers scared to turn the page?  Well you’ve got me.  Fine.  You win.

Alright, here we go, the New Yorker has an interactive map of the rise of the microbrews.  Little known fact:  there was an award winning microbrew in Texas named after me.  True story.

This here is possibly the most joyous/beautiful practical joke/prank I’ve ever seen.  It made me smile.

These are some pretty cool illustrations about how chemistry works.

Looking for some more summer reading?  How about a book that will tell you “what would Jesus drink?“

In other DNA related news, Scalia’s dissenting opinion regarding DNA sampling in Maryland v King was my favorite thing I read this week.

There’s some interesting math behind the practice of using DNA matching as sole proof in criminal cases.  The stats are normally presented to the jury as though it was a one in five million chance the person is innocent…but if the size of DNA databases starts to grow, that could lead to several hits.  Additionally, the stats do not factor in the chance that the sample was contaminated, or the chance that your DNA ended up somewhere randomly rather than intentionally.

End message: it shouldn’t be treated as perfect.

A few months ago now, I decided to get my DNA sequenced through 23 and me.  I got my health results back yesterday, and while I’m still waiting on the full ancestry results, I did get one interesting piece of information:  I share an uncommonly high amount of DNA with Neanderthal’s.

There is one four-digit whole number n, such that the last four digits of n^2 are in fact the original number n. What is n?

In light of rule #6 from my post on Sunday, I thought I’d take a crack at this article I got sent by my wonderful (and single!) brother.  The headline reads “marriage from online meetings is more stable, satisfying“.  In case you’re curious, the study was sponsored by…wait for it…an internet dating site.  

I’ve written before about my 5 reasons you should check citations, and it occurred to me recently that I need to add a 6th.  Here’s my updated list, changes in bold:

I add this one on because the word “study” and “survey” get tossed around rather loosely at times.  Two examples that made me think of this:

First, from England:

Mr Gove said: “Survey after survey has revealed disturbing historical ignorance, with one teenager in five believing Winston Churchill was a fictional character while 58 per cent think Sherlock Holmes was real.”
Those surveys, the Department has now revealed in response to an FOI request, included research conducted by Premier Inn, the budget hotel chain, UKTV Gold and “an article by London Mums Magazine”. None are known for their work in this field.

Mr Gove is apparently the British equivalent of the Secretary of Education.

Second was from a website with a rather interesting name (Manboobz).  The owner was apparently reading a book in which he saw the claim that schoolgirls hit schoolboys 20 times more often than schoolboys hit schoolgirls.  Upon investigating that citation, he discovered that it was not actually a formal study, but a class project a friend of his had assigned her students at his request.

These may both be small things, and the points they make may or may not be valid…but when in doubt it’s always worth checking the source of the source.  The answers could be surprising.

Well, we hit 94 degrees in Boston today, and I’m parked on the couch with some banana peanut butter frozen yogurt and a deep thankfulness that the weekend’s upon us.  Here’s some fun links to keep you amused:

First, Jezebel covers the best/most ridiculous acapella group names.  Aural Fixation from my alma mater made it, but I was a little surprised to see that the MIT Logarhythms  didn’t get a mention.

This link actually wasn’t that fun…it was annoying.  It’s allegedly a list of “disappointing facts for geeks“…but almost the entire lists consists of “movie x made more than movie y” with none of the numbers adjusted for inflation.  My favorite from the comments section “good news for geeks…we know bad math when we see it!”

This is very cool:  Pangea with modern political borders.  Apparently I would have been living right next to Morocco.

This is my new favorite website, btw…the Dictionary of Obscure Sorrows.  An excerpt:
sonder

Alright, now some analytics you can really use…do you live in IHOP America or Waffle House America?

If that’s too lowbrow for you, how about this:  could you pass Eton’s admissions exam?