Tautological Statistics

50% of married people are women (in most countries, anyway) 100% of smokers die. Really? I know many smokers who haven't died. He didn't write "Have died" [remainder of comment deleted]

Monthly production dips 10% in February.

This statistic shows that 50% of the people who used our projects were above the Median age. But the truly shocking discovery was that 50% of the people were below the Median age.

What percentage of users are exactly the Median age? - I'm planning to study that in phase two. (From Dilbert)

Studies show that 1 out of every 2 people make up 50% of the population.

Even more shocking, as this pie graph shows, is that 75% of people comprise a whopping 3/4 of the population!

Most of the drug users in Europe used to drink Coca Cola in their youth.

68.37% of all statistics are made up!

Debunked tautological statistics

40% of all sick days are taken on Mondays and Fridays (from a Dilbert cartoon).

That's not tautological. It's evidence that the distribution is more even than some people might expect.

If this is the criterion for 'debunking', then a number of the statistics above are similarly 'debunked', particularly the February and drug users statistics. Maybe the title should be 'WellDuhStatistics...

Everyone in our group will have a birthday this year. / Everyone I know has a birthday this year. Freaky. So, no one with birthdays on the 29th of February, then? Today's homework: Determine the probability that at least one of the N people you know has a birthday on February 29, as a function of N. ;-)

President Eisenhower expressed shock when he heard that half of all Americans are of below-average intelligence. If your expectation is that America is an educated country, this is a reasonable thing to be shocked about - as long as the average was calculated based on a world-wide average.

Firstly, education != intelligence.

Secondly, if 'average' means 'mean', then the fact stated is not tautological - it tells you that the median is the same as the mean, and thus that the distribution is not skewed, which might be quite surprising. One might expect that the mean would be above the median, as the cleverest people tend to be very, very clever, whilst the stupidest people are merely very stupid (the BrassiereCurve? and all that).

Say what you will about Americans, but I have on occasion had to explain that nearly half of all Canadians have below-average intelligence. It's "nearly" and not "exactly" because, unlike astonishingly clever Canadians, astonishingly stupid Canadians die young and are under-represented in the population.

Doesn't that raise the average smarts each time it happens? A bit like the way that each time a Canadian migrates to America, the average intelligence of both countries goes up? ;-)

CategoryStatistics