In Exercises 9–12, determine whether the sampling method appears to be sound or is flawed.

Smartphone Usage In a survey of smartphone ownership, the Pew Research Center randomly selected 1006 adults in the United States.

The Pew Research Center studied smartphone usage using 1006 randomly selected adults in the United States.

In the United States, the research was based on all smartphone owners. The center, however, randomly selected only 1006 adults from the population.

When samples are collected in a manner that they are non-biased and represent the population appropriately, the sampling method can be trusted for providing accurate observations.

In this case, the survey selected the experimental units (owners of smartphones) in a clear random way. Also, the organization is a reliable research center.

As a result, the outcomes of the observations are expected to be accurate and reliable.

Thus, the sampling method appears to be without flaws.