Chapter 7 Review Questions (Key)

1. Because methods apply equally to all incidence and prevalence measures (i.e., economy of language).
2. Bias means "systematic error"
3. A crude rate is a  rate for the population that has not yet been adjusted for age or other factors. 
4. A stratum-specific rate is a rate for a subgroup in the population. 
5. A reference population is an external population used to help adjust or standardize the rate of the study population. 
6. A standard million is a age distribution for a million citizens picked at random from a reference population.
7. It means the comparison is biased (will tend to result in an erroneous conclusion) because the groups differ with respect to extraneous factors.
8. Properties of confounder: (a) the exposure is associated with the confounder (b) the confounder is independent risk factor for disease (c) the confounder in not an intermediary in causal pathway for the disease.
9. This is the directly adjusted rate.
10. Small letters, e.g., n_i, r_i.
11. Capital letters, e.g., N_i, R_i.
12. Because the residents of Florida are typically much older than the residents of Alaska.