Assignment:
QUESTIONS:
1) Researchers at Johns Hopkins decide to use a case control study design to explore the association between women with breast cancer and DDT exposure. They interview women that have breast cancer undergoing chemo at the Johns Hopkins Hospital in Baltimore in 2014 and then take blood samples to test for DDT exposure. They also enroll a group of controls (without breast cancer) in the study based on patient lists at the hospital and also test them for DDT exposure. They find that that 360 of the women with breast cancer have DDT, exposure while 1,079 do not. Among the controls 432 have DDT exposure, and 2,446 do not.
A. Create an appropriate 2x2 table for this data.
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Breast Cancer (Cases)
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No Breast Cancer (Controls)
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DDT Exposure
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NO DDT Exposure
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B. Calculate the odds ratio comparing the odds of exposure for those with breast cancer to the odds of exposure for those without breast cancer (SHOW ALL YOUR WORK).
C. Assume that this OR is significant. What does this OR mean (be specific using the context of this study)?
2. Anecdotal evidence has suggested that a specific type of oral contraceptive pill puts women at greater risk for blood clots. Researchers decide to examine this scientifically by starting a prospective cohort study. They enroll women between the ages of 15 and 45 who are using this type of oral contraceptive pill as well as similar women who are not using this contraceptive pill. At baseline none of the women had ever had a blood clot. Then they follow these study participants for 5 years, following up with them once a year to determine if they suffered from a blood clot. At the end of 5 years the researchers report the following information: Out of a total of 6000 women that were taking the oral contraceptive of interest, 575 had reported blood clots. Of the 7000 women not taking the oral contraceptive of interest, 250 reported a blood clot.
A. Create an appropriate 2x2 table for this data.
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Blood Clot
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No Blood Clot
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Oral Contraceptive (Exposure)
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No Oral Contraceptive (No Exposure)
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B. Calculate the relative risk of having a blood clot for women taking the oral contraceptive pill in question compared to those not taking the contraceptive pill in question (SHOW ALL YOUR WORK).
C. Assume that this RR is significant. What does this RR mean (be specific using the context of this study)?