Chapter 8 Review Questions (Key)
Last update 4/16/2010
- "Exposure"
- "Disease"
- True
- A positive association indicates that the exposed group has a higher
incidence of disease than the non-exposed group. A negative association
indicates that the exposed group has a lower incidence of disease than the
non-exposed group.
- False. Association does not equal causation.
- False. Absolute comparisons are made by subtraction.
- True. Relative comparisons are made by division (in the form of a
ratio).
- This is a risk difference (RD). It is
the excess number of cases in absolute terms.
- This is a relative risk (RR). The
relative risk is a “risk multiplier.”
- RD quantifies the effect of the exposure in absolute terms.
- RR quantifies the effect of the
exposure in relative terms.
- RD = 50% - 35%= 15%. This implies that, if the non-exposed group
had been exposed, there would be 15 additional cases per 100 individuals.
- RR = (50 per 100) � (35 per 100)= 1.43.
This implies the exposed group has 1.43 times the risk of the non-exposed
group (equivalent to a 43% increase in risk, relatively speaking).
- RR
- No
- 40%
- False
- True
- The baseline RD is 0.
- It changes the sign of the risk difference from positive to
negative or vice versa.
- This suggests there are 54.3 fewer deaths per 10,000
person-years with improved physical fitness (in this particular
population).
- The baseline RR is 1.
- It changes to risk ratio to it's
reciprocal. For example, an RR of 2 becomes 1/2 = 0.5.
- The exposure increases risk by 0.85 or 85%.
- AFe
- AFp
- Because there are multiple ways to prevent any given case (see
causal pie model).
- The AFp
applies to the entire population. The AFe
applies only to exposed cases.
- a = RD, b = RR, c = AF