A recent headline: Here’s how the ACS is implemented (from Wikipedia): The ACS has an initial sample of approximately 3 million housing unit addresses and group quarters in the United States, with sample selected from all counties and county-equivalents, American Indian and Alaska Native area, and Hawaiian Homeland, and in Puerto Rico annually. Data are collected primarily by mail, with follow-ups by [...]
Read the following poll on the attitudes of working doctors: http://www.doctorsandpatients.org/images/files/DPMA_SurveyResults.pdf 1. Refresh your understanding of non-response bias. Is the response rate sufficient to exclude non-response bias? Why or why not? 2. Response bias (as opposed to non-response bias) deals with the tendency of people to answer poll questions in a way to achieve some [...]
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After nutritional labeling went into effect in New York City, a large sample of people were polled about how the label affected their behavior — 27% reported the new labels influenced their behavior, and 10% of people reported purchasing fewer calories as a result. However, when researchers looked at the average amount of calories purchased [...]