If you are conducting a case control study and you select your cases based on existing (prevalent) cases of disease inst...
If you are conducting a case control study and you select your cases based on existing (prevalent) cases of disease instead of incident (newly diagnosed) cases, how is this likely to influence your results?
a)cases are more likely to have longer survival times
b) controls will have longer survival times
c) results will be biased away from the null hypothesis
Homework Answers
Correct option:
(a) cases are more likely to have long survival times
Explanation:
Inclusion of prevalent cases leads to over - representation of cases of long duration.
Add Answer to:
If you are conducting a case control study and you select your cases based on existing (prevalent) cases of disease inst...
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10. For the case-control study scenario, how would you define your cases (disease status). Make sure to include the pop...
10. For the case-control study scenario, how would you define
your cases (disease
status). Make sure to include the population.
11. How will you identify cases/how will you gather information
on them?
12. How would you define your controls? Make sure to include the
population.
13. How will you identify controls/how will you gather
information on them?
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1 points Save Ans Regarding the selection of controls for a new case-control study of college...
1 points Save Ans Regarding the selection of controls for a new case-control study of college students at Texas A&M University, which of the following are true you may select more than one)? a. Random digit dialing may be used to generate controls, but the utility of this approach is likely less than it used to be given the predominance of cell phones and paucity of land lines. b. Depending on the research question, one individual student may in some...
An investigator conducted a case-control study in 1000 participants (500 cases and 500 controls) ...
An investigator conducted a case-control study in 1000 participants (500 cases and 500 controls) to examine the association between childhood head trauma (exposure) and Parkinson’s disease(outcome). Information on head trauma was self-reported by study participants. Cases were able to correctly report exposure to head trauma 96% of the time, while controls correctly reported exposure to head trauma 80% of the time. Cases and controls correctly reported no exposure to head trauma 96% and 98% of the time, respectively. The truth(which...
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Suppose you conduct a case-control study of endometrial cancer, with 200 cases and 200 unmatched controls....
Suppose you conduct a case-control study of endometrial cancer, with 200 cases and 200 unmatched controls. According to medical records (which we will assume are correct), 150 of the cases and 100 of the controls have used postmenopausal estrogens. (a) Construct the appropriate 2x2 table, and compute and interpret the odds ratio for endometrial cancer associated with postmenopausal estrogen use.
In a case control study of the association between obesity and late onset menopause, you think...
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Suppose a case-control study asked 238 lung cancer patients and 428 controls (matched to the cases...
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10. For the case-control study scenario, how would you define
your cases (disease
status). Make sure to include the population.
11. How will you identify cases/how will you gather information
on them?
12. How would you define your controls? Make sure to include the
population.
13. How will you identify controls/how will you gather
information on them?
High levels of job stress Little/ no job stress Hypertension No Hypertension Total 385 15,425 15,810 233 12,703 12,936 618 28,128 28,746 Total
1 points Save Ans Regarding the selection of controls for a new case-control study of college students at Texas A&M University, which of the following are true you may select more than one)? a. Random digit dialing may be used to generate controls, but the utility of this approach is likely less than it used to be given the predominance of cell phones and paucity of land lines. b. Depending on the research question, one individual student may in some...
A study comparing smokers to non-smokers history as a risk factor for Parkinson's Disease reports an incidence rate ratio of 0.3 comparing smokers to non-smokers. Explain your answers. 1) What is the study design? 2) If the association is real, do these findings indicate an increase or decrease in risk for Parkinson's disease? 3) A case-control study comparing Alzheimer's cases to controls reported cases were less likely to have reported past smoking. What kind of bias may explain these results?
Suppose a case-control study asked 238 lung cancer patients and 428 controls (matched to the cases by age and sex) whether they had kept a pet bird during adulthood. Of the 238 lung cancer cases, 99 said yes. Of the 428 controls, 102 said yes. (a) Construct a contingency table for the data. Lung Cancer No Lung Cancer Total Bird No Bird Total (b) Compute the risk (as a %) of lung cancer for bird and non-bird owners for this...
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