SOLUTION: A fast food chain store conducted a taste survey before marketing a new hamburger. The results of the survey showed that 70% of the people who tried it liked the hamburger. Assume

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Question 350023: A fast food chain store conducted a taste survey before marketing a new hamburger. The results of the survey showed that 70% of the people who tried it liked the hamburger. Assume that 70% of all people like this hamburger. On a certain day, 8 customers bought it for the first time.
(b). Find the probability that at least 5 people like the hamburger.
(c). Find the probability that at most 4 people like the hamburger.
(d). What is the expected number of people who will like the hamburger ?
(e). Find the standard deviation of the number of people who like the hamburger.
Answer by edjones(8007) (Show Source):
You can put this solution on YOUR website!
Let x=.7 and y=.3
Expand the binomial (x+y)^8
.
b) x^8+8x^7y+28x^6y^2+56x^5y3=.8059
.
c)1-.8059=.1941
.
d)8*.7=5.6
.
e)standard deviation for a binomial distribution is sqrt(n*p(1-p))=
sqrt(8*.7*.3)=1.2961
.
Ed