Question 31

True or False: In a cross-sectional study exposure and outcome are assessed at different times.

Group of answer choices

True

False

Question 32

True or False: Loss to follow-up is an important concern with both cohort and experimental studies.

Group of answer choices

True

False

Question 33

True or False: In matched case-control analysis, the discordant cells of the 2x2 table, cells "b" and "c", are disregarded when calculating the OR.

Group of answer choices

True

False

Question 34

Factor A, B, or C can each individually cause a certain disease Y without the other two factors, but only when followed by exposure to factor X. Exposure to factor X alone does not cause disease, but the disease never occurs in the absence of exposure to factor X. Factor X is a:

Group of answer choices

A. Necessary and sufficient cause

B. Sufficient, but not necessary cause

C. Necessary, but not sufficient cause

D. Neither necessary nor sufficient cause

Question 35

Choose the best option for each statement.

Group of answer choices

A method of controlling confounding employed in the design stage of a study.

[ Choose ] Information Bias Healthy Worker effect Stratification Internal validity Selection Bias Hawthorne effect External validity Restriction

Errors in the process of identifying the study population.

[ Choose ] Information Bias Healthy Worker effect Stratification Internal validity Selection Bias Hawthorne effect External validity Restriction

Subjects change their behavior because they know they are being studied.

[ Choose ] Information Bias Healthy Worker effect Stratification Internal validity Selection Bias Hawthorne effect External validity Restriction

Reflects proper selection of study groups and a lack of error in measurement.

[ Choose ] Information Bias Healthy Worker effect Stratification Internal validity Selection Bias Hawthorne effect External validity Restriction

Question 36

Several studies have found that approximately 85% of cases of lung cancer are due to cigarette smoking. This measure is an example of:

Group of answer choices

A. Incidence rate

B. Attributable risk

C. Relative Risk

D. Proportional mortality ratio

E. Odds ratio

The following information is to be used to answer questions 37-42:

A pediatrician wished to determine the relationship between chronic otitis media (OM) in young children and parental history of such infections (family history). From the records of a large pediatric practice, he identified 50 children between one and three years of age who had experienced at least three middle ear infections in the preceding year (recurrent OM). Fifty children treated for illnesses other than OM by the same group practice were also identified. The pediatrician interviewed the parents of subjects in both groups to determine the parents' history of OM when they were young children (family history). Of the children with recurrent ear infections, 30 had a family history of chronic OM compared to 20 of the children treated for other illnesses.

	D+	D-	Totals
E+
E-
Totals

Question 37

A pediatrician wished to determine the relationship between chronic otitis media (OM) in young children and parental history of such infections (family history). From the records of a large pediatric practice, he identified 50 children between one and three years of age who had experienced at least three middle ear infections in the preceding year (recurrent OM). Fifty children treated for illnesses other than OM by the same group practice were also identified. The pediatrician interviewed the parents of subjects in both groups to determine the parents' history of OM when they were young children (family history). Of the children with recurrent ear infections, 30 had a family history of chronic OM compared to 20 of the children treated for other illnesses.

Use the information from the above scenario to complete the 2 x 2 table (Please use the "Table" function and enter your table in the space below):

	D+	D-	Totals
E+
E-
Totals

Question 38

What kind of study is this?

Group of answer choices

A. Cross-sectional study

B. Prospective cohort study

C. Case-control study

D. Randomized controlled clinical trial

Question 39

What is the appropriate measure of association for this study?

Group of answer choices

A. Prevalence ratio

B. Odds ratio

C. Correlation coefficient

D. Risk ratio (relative risk)

E. Risk difference

Question 40

What is the calculated value for the correct measure of association?

Group of answer choices

A. 0.44

B. 1.20

C. 1.50

D. 2.25