Smartphone adoption among younger adults has increased substantially and mobile access to the Internet is pervasive. Fifteen percent of young adults in one study are "smartphone-dependent," meaning that they do not have home broadband service and have limited options for going online other than their mobile device. Consider a sample of 9 young adults selected. Complete parts (a) through (d) below.

a. What is the probability that 2 are

smartphone-dependent?

The probability is

b. What is the probability that at least 2 are

smartphone-dependent?

The probability is

c. What is the probability that at most 1 is

smartphone-dependent?

The probability is

d. If you selected a sample in a particular geographic area and found that none of the

9

respondents are smartphone-dependent, what conclusions might you reach about whether the percentage of smartphone-dependent young adults in this area was

15%?

Select the correct choice below and fill in the answer box to complete your choice.(Type an integer or decimal rounded to four decimal places as needed.)

A.

Since the probability of a sample in which none of the 9 respondents are smartphone-dependent is

respondents are smartphone-dependent is ---------- there is no reason to question the given percentage because this probability indicates that such a sample

isreasonable.

B.

Since the probability of a sample in which none of the 9 respondents are smartphone-dependent is

respondents are smartphone-dependent is --------- there is reason to question the given percentage because this probability indicates that such a sample

isnotreasonable.