According to analmanac,

70% of adult smokers started smoking before turning 18 years old. When technology isused, use the Tech Help button for further assistance.

(a) Compute the mean and standard deviation of the random variableX, the number of smokers who started before 18 in400

400trials of the probability experiment.

(b) Interpret the mean.

(c) Would it be unusual to observe360

360smokers who started smoking before turning 18 years old in a random sample of400

400adultsmokers? Why?

(a) mu Subscript x

xequals

=

sigma Subscript x

xequals

=

(Round to the nearest tenth asneeded.)

(b) What is the correct interpretation of themean?

A.

It is expected that in50% of random samples of400

400adultsmokers,280

280will have started smoking before turning 18.

B.

It is expected that in a random sample of400

400adultsmokers,280

280will have started smoking after turning 18.

C.

It is expected that in a random sample of400

400adultsmokers,280

280will have started smoking before turning 18.

(c) Would it be unusual to observe

360smokers who started smoking before turning 18 years old in a random sample of400

400adultsmokers?