Section_2.4_-_Cautions[1]

Section_2.4_-_Cautions[1] - lung cancer. 3. For a group of...

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Homework for section 2.4 1. Make sketches of scatterplots with - a. strong association that is not linear. b. an influential observation. c. an outlier that is not influential. 2. Doll’s data on cigarette smoking and lung cancer deaths was data for entire countries. For each statement below, say whether it is true or false : a. Doll’s correlation is an ecological correlation. b. Doll’s correlation appears stronger than it would be for individuals c. Doll’s correlation appears weaker than it would be for individuals. d. In these countries, countries with higher rates of cigarette smoking had higher rates of lung cancer deaths. e. In these countries, people who smoked more had higher chances of dying of
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Unformatted text preview: lung cancer. 3. For a group of high school students, the association between time spent on homework and GPA was r = .6. For a group of college students, the correlation was r = .7. For each statement below, say whether it is true or false : If I combine all of the students into one group, then the correlation. .. a. will be between .6 and .7. b. will be more than .7. c. will be positive. d. could take almost any value - it could even be negative. e. could not possibly be equal to 1.0. 4. Give an example of an association that is the result of a lurking variable. Identify the explanatory and response variables in your example. Explain how the lurking variable produces the association....
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This note was uploaded on 09/23/2011 for the course MATH 324 taught by Professor Staff during the Spring '08 term at S.F. State.

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