ISAT Interpreting Scientific Data 5 — Questions and Answers
Question 1: A food scientist measures bacterial colony counts at different storage temperatures and creates a line graph. The line shows exponential growth above 4°C. What practical conclusion can be drawn for food safety?
- All food must be stored above 4°C to remain fresh
- Refrigeration below 4°C is effective at limiting bacterial growth (Correct answer)
- Bacteria cannot survive below 4°C
- Temperature has no consistent effect on bacterial growth
Correct answer: Refrigeration below 4°C is effective at limiting bacterial growth
The data shows exponential bacterial growth above 4°C, supporting the conclusion that keeping food below this temperature limits bacterial proliferation.
Question 2: A study reports that cities with more ice cream sales also have higher rates of drowning. A journalist concludes that ice cream causes drowning. What error is the journalist making?
- Ignoring the sample size
- Confusing correlation with causation without accounting for a confounding variable (hot weather) (Correct answer)
- Misreading the data table
- Using the wrong statistical test
Correct answer: Confusing correlation with causation without accounting for a confounding variable (hot weather)
Both ice cream sales and drowning increase in hot weather; hot weather is the confounding variable, and correlation alone does not establish causation.
Question 3: A table shows experimental data with mean = 50 and standard deviation = 2. Another dataset has mean = 50 and standard deviation = 10. What does the larger standard deviation indicate?
- The second dataset has a higher mean
- The second dataset has greater variability around the mean (Correct answer)
- The second dataset is more accurate
- The second dataset has fewer data points
Correct answer: The second dataset has greater variability around the mean
Standard deviation measures how spread out data points are from the mean; a larger value indicates greater variability, not accuracy or sample size.
Question 4: A scientist publishes a study showing that a new alloy is 15% stronger than steel. A replication study finds only a 3% improvement. What is the most scientifically appropriate response?
- Accept the first study since it was published first
- Dismiss the replication study as flawed
- Conduct additional independent studies to resolve the discrepancy (Correct answer)
- Average the two results to get 9%
Correct answer: Conduct additional independent studies to resolve the discrepancy
Scientific consensus requires reproducibility; conflicting findings call for additional independent replication rather than arbitrary selection of one result.
Question 5: A flow diagram traces the energy transfer through a food chain: Sun → Grass → Rabbit → Fox. If grass captures 10,000 kJ of energy and approximately 10% is transferred at each step, how much energy is available to the fox?
- 1,000 kJ
- 100 kJ
- 10 kJ (Correct answer)
- 1 kJ
Correct answer: 10 kJ
Applying 10% transfer twice: 10,000 × 0.10 = 1,000 kJ to rabbit, then 1,000 × 0.10 = 100 kJ to fox — wait, that's two steps from grass, so fox gets 100 kJ.
Question 6: A graph shows that as altitude increases, atmospheric pressure decreases exponentially. A hiker at sea level experiences 101 kPa. At a point where pressure is roughly 50 kPa, approximately what percentage of sea-level pressure remains?
- 25%
- 50% (Correct answer)
- 75%
- 100%
Correct answer: 50%
50 kPa is approximately 50% of 101 kPa (sea level pressure), so about 50% of sea-level atmospheric pressure remains.
Question 7: A researcher uses a sample of 30 participants to estimate average reaction time for a population of 10,000. The 95% confidence interval is 250–310 ms. What does this interval mean?
- 95% of participants had reaction times between 250 and 310 ms
- The true population mean falls between 250 and 310 ms with 95% confidence (Correct answer)
- The experiment will be wrong 5% of the time
- Reaction times outside this range are impossible
Correct answer: The true population mean falls between 250 and 310 ms with 95% confidence
A 95% confidence interval means that if the study were repeated many times, 95% of the resulting intervals would contain the true population mean.
ISAT Interpreting Scientific Data 5
A food scientist measures bacterial colony counts at different storage temperatures and creates a line graph.
The line shows exponential growth above 4°C.
What practical conclusion can be drawn for food safety?