Name: ________________________
Instructions: For each of these studies, complete the 2x2 table, identify the correct measure of association (based on the study design), calculate and interpret the correct measure of association. The only measures of association that you will use in this assignment are the odds ratio (OR) and incidence relative risk (IRR)
You will be graded on identifying the correct measures of association, calculations (including completion of the 2x2 table as shown in class and showing your work for calculations) and your interpretations. Your interpretations must be specific and will be graded on accuracy, correct use of scientific terminology, professional writing style, grammar and spelling. You must use the 3rd
person for this assignment.
1) A study followed 80,000 pregnant women, 20% of whom had group B streptococcus (GBS). The women were followed from their first prenatal visit until they gave birth. A total of 8,000 of the women with GBS developed preeclampsia (gestational hypertension) and 2,000 of the women who did not have GBS developed preeclampsia.
a) Complete the contingency table as shown in class.
|
|
Streptococcus
|
Total
|
Incidence Rate
|
Pregnant Women
80,000
|
Yes
|
No
|
|
|
8,000
|
2,000
|
|
|
|
|
|
|
b) Is an
odds ratio
or
incidence
relative risk
more appropriate for this study?
c) Calculate the measure of association that you identified in b. Remember to show your work.
d) Write an interpretation for the measure of association that you calculated in c. You must specify the exposure and outcome in your answer.
2) Sixty cases of hepatitis A were diagnosed in one town in Australia and a case-controls study was conducted to identify the cause of the outbreak. Forty of the cases had eaten frozen pomegranate arils. Eight of the 50 controls had eaten frozen pomegranate arils.
a) Complete the contingency table as shown in class.
b) Is an
odds ratio
or
incidence r
elative risk
more appropriate for this study?
c) Calculate the measure of association that you identified in b. Remember to show your work.
d) Write an interpretation for the measure of association that you calculated in c. You must specify the exposure and outcome in your answer.
3. A cross-sectional study was conducted to investigate possible differences between mothers (n=400) and fathers (n=250) in the use of social media to research health information for their young children. Most (n=275) of the mothers used social media as a source of health information, compared with 100 of the fathers. (Hint: mothers were considered to be the “exposed” group.)
a) Complete the contingency table as shown in class.
b) Is an
odds ratio
or
incidence
relative risk
more appropriate for this study?
c) Calculate the measure of association that you identified in b. Remember to show your work.
d) Write an interpretation for the measure of association that you calculated in c. You must specify the exposure and outcome in your answer.