According to an​ almanac, 80​% of adult smokers started smoking before turning 18 years old.   ​(a) Compute the mean and standard deviation of the random variable​ X, the number of smokers who started before 18 in 300 trials of the probability experiment. ​(b) Interpret the mean. ​(c) Would it be unusual to observe 255 smokers who started smoking before turning 18 years old in a random sample of 300 adult​ smokers? Why?         Question content area bottom Part 1 ​(a) μx=enter your response here Part 2 σx=enter your response here ​(Round to the nearest tenth as​ needed.) Part 3 ​(b) What is the correct interpretation of the​ mean?     A. It is expected that in a random sample of 300 adult​ smokers, 240 will have started smoking before turning 18.   B. It is expected that in a random sample of 300 adult​ smokers, 240 will have started smoking after turning 18. C. It is expected that in​ 50% of random samples of 300 adult​ smokers, 240 will have started smoking before turning 18. Part 4 ​(c) Would it be unusual to observe 255 smokers who started smoking before turning 18 years old in a random sample of 300 adult​ smokers?     A. ​Yes, because 255 is between μ−2σ and μ+2σ.   B. No​, because 255 is greater than μ+2σ.   C. Yes​, because 255 is greater than μ+

Calculus For The Life Sciences
2nd Edition
ISBN:9780321964038
Author:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Publisher:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Chapter13: Probability And Calculus
Section13.2: Expected Value And Variance Of Continuous Random Variables
Problem 10E
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Question
According to an​ almanac,
80​%
of adult smokers started smoking before turning 18 years old.
 
​(a) Compute the mean and standard deviation of the random variable​ X, the number of smokers who started before 18 in
300
trials of the probability experiment.
​(b) Interpret the mean.
​(c) Would it be unusual to observe
255
smokers who started smoking before turning 18 years old in a random sample of
300
adult​ smokers? Why?
 
 
 
 

Question content area bottom

Part 1
​(a)
μx=enter your response here
Part 2
σx=enter your response here
​(Round to the nearest tenth as​ needed.)
Part 3
​(b) What is the correct interpretation of the​ mean?
 
 
A.
It is expected that in a random sample of
300
adult​ smokers,
240
will have started smoking before turning 18.
 
B.
It is expected that in a random sample of
300
adult​ smokers,
240
will have started smoking after turning 18.
C.
It is expected that in​ 50% of random samples of
300
adult​ smokers,
240
will have started smoking before turning 18.
Part 4
​(c) Would it be unusual to observe
255
smokers who started smoking before turning 18 years old in a random sample of
300
adult​ smokers?
 
 
A.
​Yes, because
255
is between
μ−2σ
and
μ+2σ.
 
B.
No​,
because
255
is greater than μ+2σ.
 
C.
Yes​,
because
255
is greater than μ+2σ.
 
D.
No​,
because
255
is between μ−2σ and μ+2σ.
 
E.
​No, because
255
is less than
μ−2σ.
 
 
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ISBN:
9780321964038
Author:
GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Publisher:
Pearson Addison Wesley,