"Jet" <thatjetnospam at yahoo.com> wrote in message
news:3D35D71A.36E73264 at yahoo.com...
>>> John Knight wrote:
> >
> > "Jet" <thatjetnospam at yahoo.com> wrote in message
> > news:3D353D8F.8A736C4B at yahoo.com...> > >
> > >
> > > Bob LeChevalier wrote:
> > > >
> > > > "John Knight" <johnknight at usa.com> wrote:
> > > > >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.
> > > >
> > > > This makes the assumption that those who know nothing guess
randomly.
> > IN
> > > > reality, we don't know that people guess randomly when faced with a
test
> > > > question they do not understand. Indeed, we know that they do not.
> > > >
> >
> > Wrong. Dead wrong. You could make that argument about one question,
but
> > when the pattern is repeated over and over again, then you can detect a
> > pattern: American girls scored lower on many questions than if they'd
just
> > guessed because they didn't have a clue about what the answer was.
>> Do you? Give us the answer, and the explanation, so we know you are not
> guessing.
>> Many of
> > these questions had zero misses [read: 0% failed to provide an answer at
> > all], which means you're nuts to even hint that "Indeed, we know that
they
> > do not" "guess randomly".
> >
> > The ONLY time you could apply that argument is when a large percentage
of
> > them answered correctly, but even then, if 0% failed to respond at all,
then
> > some of them HAD to guess.
>> Well, that's a reasonable assumption, but so what? Some people probably
> guess on every multiple choice question on ever test.
You and I agree. LeChevalier is an idiot. He said, and I quote: "we don't
know that people guess randomly when faced with a test question they do not
understand. Indeed, we know that they do not".
This is not the stupidest thing he's ever said. And he'll deny even said it
as time goes by. But only a real moron "thinks" like this.
>> >
> > > > But the assumption becomes totally meaningless if in fact they know
> > > > SOMETHING. If 100% of them know something, but not enough to solve
the
> > > > problem, then it is quite plausible that 100% of them will get the
> > answer
> > > > wrong. Thus someone knowing Newtonian physics perfectly will get
the
> > wrong
> > > > answer on a question that uses special relativity theory. A good
test
> > > > designer will know that the Newtonian approximation is a likely
error,
> > and
> > > > will include that answer among the incorrect alternatives.
> > >
> > > Then the article makes the shockingly stupid conclusion that NONE of
the
> > > girls who got the answer right understood the problem!
> > >
> >
> > If guessing on a multiple choice question would yield 25% correct, but
> > American girls only got 5% correct, then how would YOU calculate how
many of
> > them understood the problem?
>> Maybe 95% of the girls didn't understand the question, 5% did. Um, duh.
You don't seem to understand the point either. If *all* students just
*guessed* on a four part multiple choice question, and didn't have a clue
about what the answer was, they would have gotten 25% of them correct just
by chance.
The only way for them to get less than 25% correct would be to know
something about the problem and select the wrong answer on purpose, or to
have the wrong information in the first place.
If 30% of them got it correct, this doesn't mean that 30% of them knew the
answer. If they didn't have the wrong information, or didn't make an error,
then of the 30% who got it correct, 23% would have gotten it correct because
they guessed, and only 7% would have gotten it correct because they
understood the problem [ x = total guesses, 0.25x = correct guesses 0.75x =
wrong guesses = 70%, x = .93, 0.25x = .23 = correct guesses, correct total
answers of 30% - 23% correct guesses = 7% (those who knew the problem)].
>> >
> > > >
> > > > >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.
> > > >
> > > > But you have no evidence that any kid "guessed" on any problem.
> > > >
> > > > >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?
>> This would only make sense if everyone in the group knew they didn't
> know, and just started guessing.
>
Which was the case for many of the questions that American girls answered.
You can't score that low, consistently, if you know something about the
subject
> > > >
> > > > Wrong. I would think that if the question were difficult and well
> > designed,
> > > > that this would be quite possible.
> > > >
> > > > >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?
> > > >
> > > > I've given an explanation, and mine explains how on question D12,
both
> > boys
> > > > and girls in the US scored less than 17% and South Africans scored
only
> > 6.4%
> > > > correct.
> > >
> > > Isn't it odd that someone who is harping on math ability doesn't seem
to
> > > realize that 17 and 6 are both lower than 25? :)
> > >
> > > J
> >
> > What's your point, J?
>> My point is that you illustrate the saying, "Figures don't lie, but
> liars sure can figure."
>> You figure because American girls got a score of 22.something correct on
> one test question on one test, that there is no such thing as "gender
> equality".
>
No. I figure because American girls consistently scored lower than if
they'd just guessed on a number of problems, not just one, and because this
is a pattern that's repeated in many other tests, that they were either
misinformed in the classroom, or didn't believe what they were taught and
went with "intuition" instead of facts (or a combination).
American boys didn't do that much better, btw, which is another thing that I
figure.
> Who exactly do you think made the point that getting
> > 17% correct on a four part multiple guess problem is a lower score than
if
> > everyone just guessed?
>> You?
>> >
> > What part of that don't you understand (other than the typical and
> > infinitely STUPID statement by lojbab that no students guessed)?
>> He never made that statement.
>> J
>
And I quote: "we don't know that people guess randomly when faced with a
test question they do not understand. Indeed, we know that they do not".
Do you agree with that statement, J?
John Knight
