Okay, after typing out something long and boring... here's the short version:
20 item test, 3 people taking it. One is a good guesser. One is an average
guesser, and the other is a lousy guesser. Each gets 15 items correct and
guess on the other 5. And we assume that each question has 5 options and so
people on average will get 1 out of 5 correct.
Test is scored using the formula: NC-(1/4 # wrong)=score
NC= number correct
GC= guessed correct
GW= guessed wrong
PC= point change (+ or -) because of guessing
Person NC GC GW PC Raw Score
1 (good) 15 2 3 +1.25 16.25
2 (average) 15 1 4 0 15
3 (lousy) 15 0 5 -1.25 13.75
So, in this case guessing helped 1 of the people, didn't make any
difference for the average, but it did hurt one of them.
And all of this assumes that they really got all 15 of the items correct
that they did not "guess" at. Which, as you might have noticed some
students KNOW the answer and didn't guess... but they still got the
question wrong.
So, will guessing ALWAYS help, no. But it will help more people than it
hurts... and of course, if they can eliminate an option and improve their
chances of getting a question right, it is more likely to help them to guess.
- Marc
(who is procrastinating on grading papers)
G. Marc Turner, MEd
Lecturer & Head of Computer Operations
Department of Psychology
Southwest Texas State University
San Marcos, TX 78666
phone: (512)245-2526
email: [EMAIL PROTECTED]
