SOLUTION: 24. Suppose that a statistics class is being given an 8 question multiple choice quiz; there are 4 choices for each question with only 1 correct answer. If I. M. Lucky guesses on

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Question 870416: 24. Suppose that a statistics class is being given an 8 question multiple choice quiz; there are 4 choices for each question with only
1 correct answer. If I. M. Lucky guesses on each question, what is the probability that he gets at most 4 questions correct?
(A) 0.03 (B) 0.09 (C) 0.97 (D) 0.50 (E) 0.11
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
p(correct) = .25, n = 8
P(x ≤ 4 correct) = binomcdf(8, .25 , 4) = .9727 0r 97.27% chance
Above shows the Use of the TI Caclulator
One may use on-line calculators: recommend stattrek.com
0r one can obtain answer 'by hand'
P+%28x%29=+highlight_green%28nCx%29%28p%5Ex%29%28q%29%5E%28n-x%29+
P(x ≤ 4 correct) = P(x=0) + P(x=1) + P(x=2) + P(x=3) + P(x = 4)
P(x=0) = highlight_green%288C0%29%28.25%5E0%29%28.75%29%5E%288%29+
P(x=1) = highlight_green%288C1%29%28.25%5E1%29%28.75%29%5E%287%29+
P(x=2) = highlight_green%288C2%29%28.25%5E2%29%28.75%29%5E%286%29+
P(x=3) = highlight_green%288C3%29%28.25%5E3%29%28.75%29%5E%285%29+
P(x=4) = highlight_green%288C4%29%28.25%5E4%29%28.75%29%5E%284%29+
for cumulative Probabilities, recommend Calculator