Question

For questions 1-2, refer to the results from a hypothetical case-control study below:

	Lung cancer cases	Controls
Persons who smoked at least a pack of cigarettes per day	120	50
Persons who smoked less than a pack of cigarettes per day	60	150

Question 1 (1 point)

Calculate the prevalence of smoking at least a pack of cigarettes per day in persons with lung cancer:

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Question 2 (1 point)

Calculate the prevalence of smoking less than a pack of cigarettes per day in persons withoutlung cancer:

Question 2 options:

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Question 3 (1 point)

A case-control study design is warranted (as opposed to a cohort study or randomized trial design) when:

Question 3 options:

a)	the health condition being studies is rare

b)	the etiology of a health condition has been determined

c)	the etiology of a health condition has not been determined

d)	both "a" and "b"

e)	both "a" and "c"

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Question 4 (1 point)

In an ecological design, the planned unit of analysis is:

Question 4 options:

a)	the individuals being studied

b)	the group being studied

c)	the controls being studied

d)	the cases being studied

Question 5 (1 point)

In a cross-sectional study design, which of the following are true?

Question 5 options:

a)	exposure and disease outcome are determined simultaneously

b)	the incidence of exposure and disease can be estimated

c)	the temporal nature of exposure and disease can be established

d)	all of the above

Answer 1

1. & 2 from the above questions prevalace is mainly calculated for cross sectional studies, clear the question once more

3. Case control study is necessitate when the etiology of the disease condition hasnot been determined
4. In ecological study the planned unit of analysis is the group being studied,the main purpose of the study is to make large scale comparisons

5. In cross sectional studies exposure and disease outcome are determined simultaneously, it is an observational study nd also known as prevalance study