SOLUTION: In a recent study, it was found that 40% of customers are unsatisfied with their bank. In a sample of 25 customers, what is the probability of finding at least 15 unsatisfied custo

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Question 899355: In a recent study, it was found that 40% of customers are unsatisfied with their bank. In a sample of 25 customers, what is the probability of finding at least 15 unsatisfied customers?
Answer by reviewermath(1029) About Me  (Show Source):
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Q:
In a recent study, it was found that 40% of customers are unsatisfied with their bank. In a sample of 25 customers, what is the probability of finding at least 15 unsatisfied customers?
A:
Let X = number of unsatisfied customers in a sample of 25 customers
X ~ Binomial (n = 25, p = 0.4)
P(X ≥ 15) = sum%28%28matrix%282%2C1%2C25%2Cx%29%29%280.4%5Ex%29%280.6%5E%2825-x%29%29%2Cx=15%2C25%29 = highlight%280.0344%29