Common Core: S-ID.9
Problem 14 of 45s12-014
Across 200 neighborhoods, the number of coffee shops and the number of dental offices have a strong positive correlation, . Which statement do these data best support?
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Solution walkthrough1:50
- These data are observational: the neighborhoods were only counted. Nobody added coffee shops to see what happened.
- says the two counts rise together in a near straight line. It says nothing about why.
- A lurking variable, the number of people living there, pushes both counts up at the same time.
- Compare neighborhoods of about the same size: the two counts no longer rise together.
- Traps: "coffee shops bring dentists" and the reverse both claim a cause. "Unrelated" ignores a strong .