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October 25, 2014

October 25, 2014

Posted by **Ben** on Wednesday, May 23, 2012 at 3:08pm.

A. What is the probability of getting an answer wrong? (Do you think they want me to ignore the ESP nugget or take it into account?)

b. Let P(x) be the probability of getting exactly x of the five answers right. Calculate p(0) through P(5)

c. What is the probability of getting at least three answers right.

- Math/Prob -
**MathMate**, Wednesday, May 23, 2012 at 3:27pmWe will have to assume the ESP estimation is correct.

The resulting distribution is binomial, with 5 questions, and probability of success p=1-0.6=0.4, q=1-p=0.6 (failure).

The probability of getting exactly n question correct (out of 5) is given by the binomial coefficient

C(5,n)p^n q^(5-n)

where C(5,n)=5!/(n!(5-n)!)

Example:

probability of getting 3 answers right

=P(3) = [5!/(3!2!)]0.4^3 0.6^2

=0.2304

To calculate the probability of getting at least three correct would be:

P(3)+P(4)+P(5)=0.317

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