brain sizes: Einstein's and women's
mats_trash at hotmail.com
Fri Jul 19 05:55:52 EST 2002
> Nice try, "mat", but you're way off. Thanks for giving it a try, though.
> P1 = P2 = P3 = P4 = 0.25
> In other words, the probability of getting one question right by guessing at
> a 4 part multiple choice question is 0.25
> But to figure the probability of getting four of the same questions right,
> not the *same* answer on each question, but the *correct* answer, you must
> add them up, which is P1 + P2 + P3 + P4 = 1.0
It is quite amusing how you spount this anti-"everything other than
me" dogma, citing test results, when you yourself are apparently akin
to two short planks.
Your math suggests that I am CERTAIN to get one answer correct if I
guess on four multiple choice questions (probability of 1). Can you
not see that this is illogical just on the basis of common sense?
thats like saying if I throw a dice six times I'm sure to throw a six,
which of course is totally dumb
> > Your assumptions are also further invalid in that you calculate the
> > number 'guessed correctly' by assuming that all who got it wrong
> > 'guessed incorrectly'. Not only is this illogical in that you are
> > characterising one group of students on the basis of another group but
> > it also leads to strange conclusions such as if 70% answer correctly,
> > 10 of this 70% of this is accounted for by correct guesses, whereas if
> > 100% answer correctly no-one guessed, since there are no incorrect
> > answers.
> No. The assumption is valid, particularly since the percent correct is
> lower than if they had just all guessed, and when all of the questions are
> answered. It's true that some of the questions might reflect some bad
> instruction in the classroom, but when the responses are spread across the
> spectrum like they were, and still the score was lower than pure guesses,
> then the only conclusion can be that they guessed on most of the questions.
You still have yet to address the conclusion that if 100% answer
correctly no-one guessed and if 0% answer correctly then something
very strange happens as the population taking the test suddenly
increases by a third but their papers are somehow lost. As you might
see from working with the latter case, your analysis does not hold.
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