Analytic epidemiologic studies are concerned with the etiology (causes) of diseases and other health outcomes. In comparison, descriptive epidemiology classifies a disease or other health outcome according to the categories of person, place, and time. The concepts of association between exposures and health outcomes should be carefully reviewed.

For this discussion, identify the type of study design that is described by each of the following statements. Ensure you provide a rationale for the identified type.

1. The association between average unemployment levels and mortality from coronary heart disease was studied in countries in New York State.

2. A group of women who had been diagnosed with breast cancer was compared with a group of cancer-free women; participants were asked whether they used oral contraceptives in the past.

3. A group of recent college graduates (exercisers and non-exercisers) were followed over a period of 20 years in order to attack the incidence of coronary heart disease.

4. A pharmaceutical company wanted to test a new medicine for control of blood sugar. Study participants were assigned randomly to either a new medication group or a group that used an older medication. The investigator and the participants were blinded as to enrollment in the study conditions.

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Epidemiologic studies may be impacted by bias.

For this discussion, please address the following:

1. Define what is meant by bias in epidemiologic studies.

2. Give examples of four types of bias. Provide an explanation for each example.

-for these two qustion the answer need to be one paragraph each.

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Ecologic studies are different from most familiar research designs and from other types of epidemiologic research.

For this discussion, please address the following:

1. State one of the most important ways in which ecologic studies differ from other observational study designs used in epidemiology.

2. What is meant by the ecologic fallacy?

3. Using your own ideas, suggest a possible design for an ecologic study; how might the study design be affected by the ecologic fallacy?

-please explanin more, do not make the answer one or two sentence, but more.

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please ensure that when you answer all qustions you but the qustions with answers, so I can know.