Answer
$\hat{p}$ = 0.150
Work Step by Step
The point estimate of the population proportion is given by $\hat{p}$ = $\frac{x}{n}$ . Here, $x$ represents the number of people in the sample with the specified characteristic and n represents the sample size.
In this question, $x$ is the number of adults, 18 and older, who have made a purchase from their smartphone. On the other hand, n is a sample size which consists of adult Americans who are 18 and older.
Therefore, $\hat{p}$ = $\frac{542}{3611}$ = 0.150
