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Basic Biostatistics

Answer the following questions covering materials from previous chapters in your textbook. Each question is worth 7 points.

1. A trial evaluated the fever-inducing effects of three substances. Study subjects were adults seen in an emergency room with diagnoses of the flu and body temperatures between 100.0 and 100.9ºF. The three treatments (aspirin, ibuprofen and acetaminophen) were assigned randomly to study subjects. Body temperatures were reevaluated 2 hours after administration of treatments. The below table lists the data.

Table: Decreases in body temperature (degrees Fahrenheit)
Group 1 (aspirin) 0.95 1.48 1.33 1.28
Group 2 (ibuprofen) 0.39 0.44 1.31 2.48 1.39
Group 3 (acetaminophen) 0.19 1.02 0.07 0.01 0.62 -0.39

Complete an ANOVA for the above. What do you conclude?

2. Evidence of nonrandom differences in group means occurs when the variance between groups is __________ the variance within groups.

3. Why are scatterplots necessary when investigating the relationship between quantitative variables?

4. r is always greater than or equal to _____ and less than or equal to _____. Perfect negative association is present when r = _____. Perfect positive association is present when r = _____. Between r = -0.56 and r = +0.46, the stronger correlation is _____.

5. Besides linearity, what conditions are needed to infer population slope ß (3 more conditions)? Besides linearity, what conditions are needed to infer population correlation coefficient ? (2 more conditions)?

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