Question

Assume that when adults with smartphone are randomly selected 49% use them in meetings or classes. if 12 adults smartphone users are randomly selected, find the probability that fewer than 4 of them use their smartphones in meetings or classes

Answer 1

Let X denote the random variable representing the number of adults who use smartphones in meetings or classes in the sample of 12 randomly selected adult smartphone users.

Now, we can assume that each adult smartphone user is independent of others and the probability of any randomly selected adult smartphone user using their smartphone in meetings or classes is 49%.

Thus, X ~ Binomial(n = 12, p = 0.49)

Thus, the pmf of X is given by:

Now, the probability that fewer than 4 of the selected 12 use their smartphones in meetings or classes is given by:

which is the required probability.

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