SOLUTION: Consider the binomial random variable�x�with�n�=�39�and�p�=�0.4. (a) Find the mean. (Give your answer correct to one decimal place.)� � (b) Find the standard deviation. (Giv

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Question 922519: Consider the binomial random variable�x�with�n�=�39�and�p�=�0.4.
(a) Find the mean. (Give your answer correct to one decimal place.)�
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(b) Find the standard deviation. (Give your answer correct to two decimal places.)�

Answer by ewatrrr(24785) (Show Source):
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p = .4, n = 39
(a) Find the mean. .4*39 = 15.6 (Give your answer correct to one decimal place.)

(b) Find the standard deviation. sqrt(.4*39*.6)= 3.06 (Give your answer correct to two decimal places.)
...........
A binomial random variable has a mean equal to 212 and a standard deviation of 8.
(a) Find the value of n. (Give your answer correct to the nearest whole number.)
np = 212,
sqrt(npq) = 8
sqrt(212q) = 8
212q = 64
q = 64/212 = 16/53 and p = 1- 16/53 = 37/53 and n = 212/p = = 304 rounded.
(b) Find the value of p. (Give your answer correct to four decimal places.)
p = 37/53 = .6981 rounded