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A statistics professor gives a surprising quiz consisting of 10 true/false questions and states that passing requires 6 correct responses. Assume that an unprepared student adopts the questionable strategy of guessing for each answer.
Find the probability that the first 6 responses are correct and the last 4 are wrong.

2007-10-25 17:26:16 · 5 answers · asked by austin 1 in Science & Mathematics Mathematics

Choose the correct statement

a. The probability of guessing correctly on the first 6 questions and incorrectly on the remainder is less than the probability of passing by guessing.

b. The probability of guessing correctly on the first 6 questions and incorrectly on the remainder is greater than the probability of passing by guessing.

c. The probability of guessing correctly on the first 6 questions and incorrectly on the remainder is the same as the probability of passing by guessing.

2007-10-25 17:41:12 · update #1

5 answers

As others have said, the probability that the first 6 are correct and the last 4 are wrong is 1/2^10 = 1/1024.

This is much smaller than the probability of passing by guessing, because there are many other ways in which you can get 6 correct questions and 4 incorrect ones; and you could also get 7, 8, 9 or 10 questions correct by guessing. Therefore (a) is correct and (b) and (c) are wrong.

2007-10-25 17:51:00 · answer #1 · answered by Scarlet Manuka 7 · 1 0

1/(2)^10 = 1/1024
as I understand the question

2007-10-25 17:38:30 · answer #2 · answered by Natali 2 · 0 0

The chance that out of:
(T/F)(T/F)(T/F)(T/F)(T/F)(T/F)(T/F)(T/F)(T/F)(T/F)
You get
(T)(T)(T)(T)(T)(T)(F)(F)(F)(F)
Guessing on each problem is merely:
(1/2)^10
or .0009765624
Essentially, there are 2^10 possible results, and TTTTTTFFFF is one of them. Another way to thing of this is 1/(2^10) which is also .0009765624.

2007-10-25 17:35:37 · answer #3 · answered by Kevin 2 · 0 0

c

2007-10-26 07:39:09 · answer #4 · answered by hayduke505 1 · 0 0

Id like to use my lifeline phone-a-friend.......wtf is this Q about again???????????

2007-10-25 17:30:12 · answer #5 · answered by JoeG 3 · 0 0

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