According to an almanac, 60% 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 400 trials of the probability experiment. (b) interpret the mean. (c) would it be unusual to observe 340 smokers who started smoking before turning 18 years old in a random sample of 400 adult smokers? why?

The Mean and standard deviation of random variable is Respectively.

The given problem describes a binomial distribution with

trials, i.e,

a)The mean is given by;

The standard deviation is given by the formula,

b)The mean means that in an experiment of adult smokers, of adult smokers started smoking before turning years old so on an average smokers who started smoking before turning years.

c)It would be unusual to observe smokers who started smoking before turning years old in a random sample of adult smokers because is far greater than the mean of the distribution.   is greater than the standard deviations from the mean of the distribution.

Learn more about Standard deviation concept here,

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a; x = 0.5

step-by-step explanation:

-10x = -5

x = 0.5