This exercise was originally developed for the Disease Detectives event
in the 2002 National Science Olympiad held at the University of Delaware
in Newark, Delaware. Winners of the event were from Harriton High School
in Rosemont, Pennsylvania.
Testing for Anthrax. Exercise and
Answer Key. PDF 211K. Learn about viewing PDF files with Adobe Acrobat.
What do Disease Detectives call a second group (such as the group of government workers) in a study?
Answer: This group is called “controls” or “the unexposed group.”
- Why would Disease Detectives test such a group? (1 point)
Answer: Controls are a comparison group from a different setting who are thought not to be exposed.
- Why did the investigators collect cultures from mill workers after they had been at work for a while rather than first thing in the morning?
Answer: The hypothesis is related to exposure at work; Disease Detectives were not investigating home
- Which occupational group had the highest prevalence of carriers of B.
anthracis? (1 point)
Answer: Combing: 6/16, about 37%
- What was the overall prevalence of carriers of B. anthracis in the mill workers?
Answer:14/101 or 14%
- None of the government workers tested positive with either test. Give a
likely explanation for this finding. (1 point)
Answer: They were not exposed.
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