If a Researcher Runs an Ad in a Paper in Order

question 15

Multiple Choice

If a researcher runs an ad in a paper in order to recruit subjects, and places the first 10 people who call in one group and the next 10 people who call in another group, what sort of threat to internal validity has been introduced?

• A) Mortality
• B) Experimenter bias
• C) Selection bias
• D) Regression effect

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Definitions:

Nonsmokers

Individuals who do not smoke cigarettes or use tobacco products, often assessed in studies for health risk comparisons.

Exposure

refers to the contact with a disease-causing factor or the amount of the factor that impinges upon a person or group.

Incidence Rate Ratio

A measure used in epidemiology to compare the rate of occurrence of new cases of a disease or condition between two study populations over a specific time period.

Population Proportion Attributable Risk

The proportion of incidents in the population that are due to the risk factor, helping in understanding the public health impact of the factor.