4. A CBS news survey reported that 72% of adults said the US treasury should continue making pennies. Suppose we select a sample of 15 adults
(a) how many of the 15 would we expect to indicate that the treasure should continue making pennies?
(b) More what is the standard deviation?
(c) what is the likelihood that exactly 7 adults would indicate the treasure should continue making pennies?
(d) what is the likelihood that at least 7 adults would indicate the treasure should continue making pennies?7 adults would indicate the treasure should continue making pennies?
4. A CBS news survey reported that 72% of adults said the US treasury should continue making pennies. Suppose we select a sample of 15 adults
(a) how many of the 15 would we expect to indicate that the treasure should continue making pennies?
(b) More what is the standard deviation?
(c) what is the likelihood that exactly 7 adults would indicate the treasure should continue making pennies?
(d) what is the likelihood that at least 7 adults would indicate the treasure should continue making pennies?7 adults would indicate the treasure should continue making pennies?
4. A CBS news survey reported that 72% of adults said the US treasury should continue making pennies. Suppose we select a sample of 15 adults
(a) how many of the 15 would we expect to indicate that the treasure should continue making pennies?
(b) More what is the standard deviation?
(c) what is the likelihood that exactly 7 adults would indicate the treasure should continue making pennies?
(d) what is the likelihood that at least 7 adults would indicate the treasure should continue making pennies?7 adults would indicate the treasure should continue making pennies?
a)
u = mean = np = 10.8
b)
s = standard deviation = sqrt(np(1-p)) = 1.73896521
c)
Note that the probability of x successes out of n trials is
P(n, x) = nCx p^x (1 - p)^(n - x)
where
n = number of trials = 15
p = the probability of a success = 0.72
x = the number of successes = 7
Thus, the probability is
P ( 7 ) = 0.024385984 [ANSWER]
****************
d)
Note that P(at least x) = 1 - P(at most x - 1).
Using a cumulative binomial distribution table or technology, matching
n = number of trials = 15
p = the probability of a success = 0.72
x = our critical value of successes = 7
Then the cumulative probability of P(at most x - 1) from a table/technology is
P(at most 6 ) = 0.009444483
Thus, the probability of at least 7 successes is
P(at least 7 ) = 0.990555517 [ANSWER]
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