Disease Detectives Practice Tests
Free, AI-generated Disease Detectives practice tests for Science Olympiad. Choose Invitational, Regional, State, or National difficulty, import past exam PDFs, and track your scores over time.
Disease Detectives runs in both Division B and Division C for the 2027 season.
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Disease Detectives Sample Practice Questions
1. At a picnic, 30 of 60 people who ate potato salad became ill. What was the attack rate among those who ate it?
- 30%
- 50%
- 60%
- 90%
Show answer and explanation
Answer: 50%
The attack rate in the exposed group is the number who became ill divided by the total who ate the salad: 30 ÷ 60 = 50%.
2. Which measure of association is appropriate for a case-control study?
- Relative risk
- Odds ratio
- Attack rate
- Prevalence
Show answer and explanation
Answer: Odds ratio
Case-control studies sample by outcome, so incidence cannot be computed - use the odds ratio, (a×d)/(b×c) from the 2×2 table. Relative risk requires cohort designs that follow exposed and unexposed groups.
3. The number of NEW cases in a population during a time period is called:
- Prevalence
- Incidence
- Case fatality rate
- Mortality rate
Show answer and explanation
Answer: Incidence
Incidence counts new cases over a period; prevalence counts all existing cases (new + old) at a point in time - a snapshot.
4. A doorknob that transmits an infectious agent is an example of a:
- Vector
- Fomite
- Reservoir
- Carrier
Show answer and explanation
Answer: Fomite
A fomite is an inanimate object that carries pathogens (doorknobs, towels, toys). A vector is a living transmitter, like a mosquito; a reservoir is where the pathogen normally lives.
5. An epi curve shows all cases clustered within one incubation period of a single exposure. This pattern is:
- Point source outbreak
- Continuous common source
- Propagated outbreak
- Endemic transmission
Show answer and explanation
Answer: Point source outbreak
A single exposure produces a sharp rise and quick fall, with all cases inside one incubation period. Continuous sources sustain cases over time; propagated outbreaks show successive, spaced waves from person-to-person spread.
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Indexed Disease Detectives Practice Tests by Difficulty
Reviewed full-length Disease Detectives practice tests, each with every question and answer choice listed on its own page.
What Disease Detectives Tests Cover
epidemiology concepts, disease transmission, outbreak investigation, study designs, and public health.
Key formulas & definitions
- Incidence rate = New cases / Population at risk × time period
- Prevalence = All cases (new + existing) / Total population (snapshot in time)
- Attack rate = Cases / Exposed population (used in outbreaks)
- Case fatality rate = Deaths / Cases × 100%
- Mortality rate = Deaths / Total population
- Relative Risk (RR) = Incidence in exposed / Incidence in unexposed (used in cohort studies)
- Odds Ratio (OR) = (a×d)/(b×c) from 2x2 table (used in case-control studies)
Study types
- Cohort: Follow exposed vs unexposed forward in time → Calculate RR
- Case-Control: Compare cases vs controls looking backward → Calculate OR
- Cross-sectional: Snapshot, measures prevalence
- Randomized Controlled Trial (RCT): Gold standard, random assignment COMMON MISTAKES: Confusing incidence (new cases) vs prevalence (all cases). Using RR for case-control studies (should use OR).