SOLUTION: Hi there, I'm really stuck on this problem and could use your help! Mimi made a random guess at 10 true-or-false questions. Let x be the number of correct answers she got. We kn

Question 1048248: Hi there, I'm really stuck on this problem and could use your help!
Mimi made a random guess at 10 true-or-false questions. Let x be the number of correct answers she got. We know that x follows a binomial distribution.

Could you identify n (number of trials), p (probability of success) and q (probability of failure) for this binomial distribution?
In addition, what is the expected value (μ) and standard deviation (σ), respectively?
Any help on this would be greatly appreciated!

Found 2 solutions by ewatrrr, rothauserc:
Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!
10 true-or-false questions
n = 10, p = 1/2 and q = 1/2
Bionomial distribution
mean = np = 10(1/2) = 5
variance = npq= np(1-p) = 5/2
SD = sqrt variance = sqrt(5/2)

Answer by rothauserc(4718) (Show Source): You can put this solution on YOUR website!
p=0.50, q=0.50, n=10
:
expected value is np = 10 * 0.50 = 5
:
std. dev. is square root(npq) = square root(10*0.50*0.50) = 1.58
:

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