"Parse Tree" <parsetree at hotmail.com> wrote in message
news:C9mY8.296$QY4.128034 at news20.bellglobal.com...
> > ALL this requires is a little bit of addition and subtraction. It
doesn't
> > require you to resolve a million third order partial differential
> equations.
> > It doesn't require calculus. It doesn't even require algebra if you do
it
> > right.
>> Statistics very much requires algebra. Calculus too, in many cases.
>>
Believe me, Parse, you don't need algebra or calculus to calculate the
statistical average for American girls in TIMSS math. Even adjusting for
guesses doesn't require anything but some very basic probability theory.
It's as simple as this:
If you're asked a question which has four multiple choice answers, and you
haven't got a clue what the answer is, what is the probability of getting a
correct answer? Since you have once chance in four of getting the right
answer, your probability is 0.25. If you guess on two questions, your
probability is .5, and three it's .75, and four, it's 1.0.
In other words, over the long run, or over millions of test takers, guessing
on such a question will yield 25% correct answers, or conversely, every
fourth answer will be correct.
No algebra. No calculus. A bit of probability theory, and you already know
that 25% of all students will get the correct answer if they only *guess* on
a four part multiple choice question.
Now here's the hard part:
Question H04 on TIMSS had four multiple choice answers, so you would think
that no country or age group or race or sex would answer less than 25% of
them correct, right? Wrong. http://christianparty.net/timssh04.htm shows
that American girls answered only 22.8% of them correct.
They scored 2.2% lower than if they'd just guessed.
How do you think that's possible?
You can probably figure this out with no knowledge of algebra or calculus,
and you already know all the probability theory that might be needed, so
what is your explanation?
John Knight
