ISAT Interpreting Scientific Data 2 — Questions and Answers
Question 1: A scatter plot shows plant height (y-axis) vs. fertilizer concentration (x-axis). The data points form a curve that rises steeply at first, then flattens. What does this pattern indicate?
- Plant height decreases as fertilizer increases
- There is no relationship between fertilizer and plant height
- Fertilizer has diminishing returns on plant growth (Correct answer)
- Plant height and fertilizer are inversely proportional
Correct answer: Fertilizer has diminishing returns on plant growth
A curve that rises then flattens indicates diminishing returns — each additional unit of fertilizer produces less additional growth.
Question 2: Two bar charts display average test scores for two schools across five years. School A's bars are consistently taller than School B's. What can be most reliably concluded?
- School A's teaching methods are superior
- School A consistently outperforms School B on average test scores (Correct answer)
- Students at School A are more intelligent
- School B will improve its scores in future years
Correct answer: School A consistently outperforms School B on average test scores
The data directly supports only the descriptive conclusion that School A had higher average scores; causal or predictive claims require additional evidence.
Question 3: A researcher reports a p-value of 0.03 for an experiment. Using a significance threshold of α = 0.05, what is the correct interpretation?
- There is a 3% chance the hypothesis is true
- The result is statistically significant (Correct answer)
- The effect size is large
- The null hypothesis is proven false
Correct answer: The result is statistically significant
A p-value below the significance threshold (0.03 < 0.05) means the result is statistically significant, allowing rejection of the null hypothesis.
Question 4: A table shows the number of bacteria (in millions) doubling every 20 minutes. If there are 2 million bacteria at time zero, how many will there be after 1 hour?
- 6 million
- 8 million
- 12 million
- 16 million (Correct answer)
Correct answer: 16 million
Doubling three times in 60 minutes: 2 → 4 → 8 → 16 million bacteria.
Question 5: A line graph shows CO₂ levels over 50 years with an overall upward trend but seasonal fluctuations. A student claims the dips in the graph prove CO₂ is decreasing. Why is this claim flawed?
- The student is confusing CO₂ with oxygen
- The student is misinterpreting seasonal variation as a long-term trend (Correct answer)
- The graph does not contain enough data points
- CO₂ levels cannot be measured seasonally
Correct answer: The student is misinterpreting seasonal variation as a long-term trend
Seasonal fluctuations are short-term oscillations that do not negate an overall long-term upward trend visible across the full data set.
Question 6: An experiment tests whether a drug lowers blood pressure. The control group receives a placebo and the treatment group receives the drug. Both groups show similar blood pressure reductions. What does this suggest?
- The drug is highly effective
- The placebo effect or other factors may account for the reduction (Correct answer)
- The experiment was conducted incorrectly
- Blood pressure cannot be measured accurately
Correct answer: The placebo effect or other factors may account for the reduction
Similar outcomes in both groups suggest the drug has no additional effect beyond what a placebo or natural variation can explain.
Question 7: A pie chart shows that 40% of survey respondents prefer Brand A, 35% prefer Brand B, and 25% prefer Brand C. The survey had 200 respondents. How many preferred Brand B?
- 35
- 50
- 70 (Correct answer)
- 80
Correct answer: 70
35% of 200 = 0.35 × 200 = 70 respondents preferred Brand B.
ISAT Interpreting Scientific Data 2
A scatter plot shows plant height (y-axis) vs. fertilizer concentration (x-axis).
The data points form a curve that rises steeply at first, then flattens.
What does this pattern indicate?