Bob LeChevalier wrote:
>> "John Knight" <johnknight at usa.com> wrote:
> >> > 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.
>> I see no reason to deny I said it. I believe it is true. People are
> incapable of behaving truly randomly. More likely, if someone were to have
> no idea what the answers were, but wanted to guess, they would mark the
> answers NON-randomly, like marking "A" for all of them or repeating a
> pattern.
>> >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.
>> But the converse is NOT true, that "if just 25% of them got the question
> correct, then all students just guessed".
>> >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.
>> A slight dawn of understanding. Of course when they "select the wrong answer
> on purpose", they don't think it is the wrong answer.
>> >If 30% of them got it correct, this doesn't mean that 30% of them knew the
> >answer.
>> It might or it might not.
>> 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)].
>> You cannot determine the percentage who guessed. You persist in assuming
> that everyone who got the answer wrong guessed randomly, and there is no
> evidence of this.
>
Let's look at his algebra. He states x = total guesses, and 0.25x =
correct guesses 0.75 x= wrong guesses.
He then figures that 0.75 x= 70%, and thus x = .93.
BUT, if we figure .25 x= 30%, x=1.20. We have x with two different
values!
LOL.
J
snip
