Math of Probability

8/14/08

It has been a very long time since I studied math of probability - so long I may
not even be able to state the name correctly. When I went to college and studied
engineering our computers were called slide rules. That should give you an idea
of just how long it has been.
What does this have to do with fly fishing for trout - in my opinion, a lot. When
you study probability you are going through the process of trying to figure out
the likelihood of something taking place. The trick is to figure out when these
"events" -they are called in math - occur. The likelihood of events occurring were
and I guess maybe still are expressed in decimals from zero to one. If the
probability of something occurring is one, it means the event is definitely is going
to occur. If the probability is zero, it is not going to occur. Decimals between
those two extremes tell you just what the probability of something happening is.
Now that we have that straight and I still haven't said what this has to do with
fishing, just let me say -"almost everything".
When we tie on a particular fly, we try to tell ourselves that the fly has a high
probability of catching a trout or at least a higher probability than the other flies
in our box. If we make a certain type of presentation we think it is going to have a
higher probability of catching a trout than another type of presentation.  If we
choose to fish in the morning instead of the afternoon, we may have convinced
ourself that the probability of catching trout is higher in the morning than it is in
the afternoon.
If I tell you there are more bigger fish in the Great Smoky Mountains National
Park this year than they were last year because I have fished there ten or a
hundred times this year -catching more bigger fish than I did last year - that
means I don't know a dang thing about math of probability.
If I tell you that I caught more fish this year than last year and that is obvious
there are more fish this year than last year; then again, I don't know anything
about math of probability.
Flip a coin fifty times. You would think the odds of it landing on heads would be
fifty percent since it only has two sides. Try it and you will find it may well land on
heads 30 or even 40 times out of 50 or maybe only 20 times out of fifty. To get
the dang coin to land on heads very close to 50 percent of the time, usually
requires flipping it a few thousand times or more, however, it may land on heads
25 out of 50 times the very first time we try it and not again for the next 1,000
times.
If I caught more fish this year than last year - fishing one hundred days this year
and I tell you that there are more fish this year than last year, I am really a little
bit nuts.  
If I caught more of them on a June Bug this year than a purple people eater fly,
again, that would not mean anything other than I happened to have caught more
fish on a June Bug fly. The Purple People Eater may still be the best fly. Let
1000 anglers fish fifty thousand days this year and fifty thousand days next year
and provide me the results, then I MAY be able to tell you for a fact if there are
more fish in the park this year than next year. I say "may" because there are too
many variables in such an undertaking.  Well, on second thought, if I had to rely
on anglers telling the truth, I wouldn't have many people reading my articles and
the statics provided too me by Yahoo, say that is not the case. There are a lot of
you -far more than I ever thought there would be. Thank all of you.  
Well, maybe I got my point across. Again, it has been a long time since I went to
college and when I did, I focused more on astronomy (the study of those
heavenly bodies) than math.

Copyright 2008 James Marsh ? - on second thought, I better not.