True-False

Question 1

When a disease is rare, the controls are representative of the target population and the cases are representative of all cases, the odds ratio estimates the risk difference

Answer 1

True

Question 2

It is possible to control for confounding during the Nakuru c phase of a study

Answer 2

True

Question 3

Bias refers to a lack of precision in a study

Answer 3

False

Question 4

Controls are needed in a case-control study to evaluate whether the frequency of a factor or past exposure among the cases is different from that among comparable persons who do not have the disease under investigation

Answer 4

True

Question 5

Both cohort and case control studies can assess the temporal sequence of exposure and disease

Answer 5

False

Question 6

Exposure based cohort studies permit investigation of exposure that are uncommon

Answer 6

True

Question 7

A causal relationship between an exposure and a disease can be established even if some of the causal guidelines are not met

Answer 7

True

Question 8

According to the sufficient component causal model, blocking the action of a necessary cause will prevent all cases of a disease by all of its causal mechanisms

Answer 8

True

Question 9

An increase study power will allow detecting a larger effect size assuming all other study parameters remain the same

Answer 9

True

Question 10

A causal relationship between an exposure and a disease can be established even if some of the causal guidelines are not met

Answer 10

True

Question 11

Secondary attack rate is used to measure infectivity

Answer 11

True

Question 12

John Snow is credited with developing the smallpox vaccination

Answer 12

False

Question 13

One of William Farrs contributions to public health and epidemiology included the development of a more sophisticated system for codifying medical conditions

Answer 13

True

Question 14

Random error occurs when there if a difference between the value of the estimate of effect in the study population and the estimate obtained from the study sample

Answer 14

True

Question 15

If we have ruled out chance and confounding as explanations for an association, we may conclude that the association is causal

Answer 15

False

Question 16

The guideline of specificity means that an exposure can cause more than one disease

Answer 16

False

Question 17

The presence of an association is indicative of a causal relationship

Answer 17

False

Question 18

Time order is an essential attribute of a cause

Answer 18

True

Question 19

Exposure to HIV is a necessary but not sufficient cause of AIDS

Answer 19

True

Question 20

In cases of fatal infection, virulence can be measured by the case fatality rate

Answer 20

True