On Tuesday, May 21, 2019 at 2:07:39 PM UTC-7, Frank Krygowski wrote:
On 5/21/2019 11:29 AM, jbeattie wrote:
On Monday, May 20, 2019 at 4:10:56 PM UTC-7, Frank Krygowski wrote:
On 5/20/2019 5:07 PM, jbeattie wrote:

Tom, statistically, you did not have any of your head injuries. They were imagined...

IOW: "Math is HARD!!!"


It's not math. It's statistics -- where two plus two may equal four, depending on who you are. Large population studies say little or nothing about the risks encountered by individual cyclists in particular areas or engaging in specific types of cycling. Tom is an example -- as are most of my cohorts. It doesn't take a math genius to recognize that lumping together the accident rates of NYC bike messengers and Sun City retirees is going to create a combined rate that is not accurate for either group.

Jay, that has nothing to do with your quip "Tom, statistically, you did
not have any of your head injuries."

Obviously, that's not what the statistics say. But unfortunately, there
are plenty of people who seriously engage in your logical fallacy. One
way it's been expressed is "Yes, there may be only one bike fatality per
ten million miles ridden. BUT WHAT IF THAT ONE IS _YOU_??"

And regarding large population studies: It's true that every large
population has its probability distribution, usually a bell curve. And
there are certainly individuals out on each tail end of each bell curve
- the good end and the bad end.

But that does not mean the studies say "little or nothing" about
individual risks. Unless the individual is riding his bike off the roof
of a skyscraper, his individual values are best thought of as
modifications of the mean value. One individual will very likely be
within two standard deviations of the mean. He's very unlikely to be
more than three standard deviations away from the mean. Or in other
words, almost everybody is almost average.

Above all, if a person chooses situations and behaviors that are well
within his skills and capabilities, he can place himself further on the
"good" side of that bell curve. If he takes excessive risks, he places
himself further toward the "bad" side.

An individual with a large number of crashes almost certainly didn't get
those because statistics failed. It's because one way or other, his
choices were bad.


--
- Frank Krygowski

The numbers of cyclists killed over decades is still way too small to make a good graph on. You are still stuck making generalities and theories. So these "I would have been killed were it not for my helmet" don't have any idea what they're talking about.