A random sample of adults in a large US city responded to a series of questions about their use of public transportation. The results of the survey showed that 520 of the 838 adults in the sample (62%) have used public transportation in the past week. How might the results of the survey be biased in obtaining an estimate of all US residents who use public transportation? -Because not all residents in this US city were asked to participate, the survey may underestimate usage of public transportation.
-Because the sample includes only residents in one US city, the survey may overestimate the proportion of US adults who use public transportation.
-Because those surveyed may choose not to answer, the survey may underestimate the proportion of US residents who use public transportation.
-Because the survey includes a random sample of residents in one US city, the survey should provide an accurate estimate of the proportion of US adults who use public transportation.