ATAR Scientific Inquiry & Understanding 4 — Questions and Answers
Question 1: The term 'validity' in an experiment refers to:
- Whether measurements are consistent across trials
- Whether the experiment actually measures what it claims to measure (Correct answer)
- Whether the sample size is large enough
- Whether results can be replicated by another lab
Correct answer: Whether the experiment actually measures what it claims to measure
Validity concerns whether the experimental design and measurements genuinely test the intended variable or concept.
Question 2: A researcher finds a strong positive correlation between two variables. This means:
- One variable directly causes the other to increase
- As one variable increases, the other tends to increase (Correct answer)
- The variables are unrelated
- The relationship is perfectly linear
Correct answer: As one variable increases, the other tends to increase
Correlation indicates a statistical association, not causation; a positive correlation means both variables tend to increase together.
Question 3: In scientific notation, the number 0.00452 is written as:
- 4.52 × 10²
- 4.52 × 10⁻³ (Correct answer)
- 45.2 × 10⁻⁴
- 0.452 × 10⁻²
Correct answer: 4.52 × 10⁻³
Moving the decimal point three places to the right gives 4.52, and the negative exponent reflects the small magnitude of the original number.
Question 4: Which of the following best defines 'reliability' in scientific experimentation?
- The experiment produces the same results each time it is repeated under the same conditions (Correct answer)
- The experiment measures what it was designed to measure
- The results agree with the accepted scientific consensus
- The sample used represents the whole population accurately
Correct answer: The experiment produces the same results each time it is repeated under the same conditions
Reliability refers to the reproducibility of results when the experiment is repeated under identical conditions.
Question 5: A student notices that plants near a window grow taller than those in the corner of the room and concludes that light increases plant growth. What is the main weakness of this conclusion?
- The student did not measure the plants often enough
- The conclusion ignores other variables like temperature and air circulation near the window (Correct answer)
- The student should have used more types of plants
- Light has already been proven to affect plant growth so no conclusion is needed
Correct answer: The conclusion ignores other variables like temperature and air circulation near the window
Without controlling for other variables such as temperature or airflow, it cannot be concluded that light alone caused the difference in growth.
Question 6: When recording a measurement of 25.0 mL rather than 25 mL, the extra zero is significant because it:
- Makes the number look more precise
- Indicates the measurement was made to the nearest 0.1 mL (Correct answer)
- Is required by ATAR examination rules only
- Shows the thermometer was calibrated correctly
Correct answer: Indicates the measurement was made to the nearest 0.1 mL
Trailing zeros after a decimal point are significant figures that convey the precision of the measuring instrument used.
Question 7: Which of the following best describes the purpose of a control group in an experiment?
- To demonstrate what happens when the experiment fails
- To provide a baseline comparison by not receiving the experimental treatment (Correct answer)
- To test multiple independent variables simultaneously
- To represent the largest sample in the study
Correct answer: To provide a baseline comparison by not receiving the experimental treatment
A control group receives no treatment and serves as a reference point to compare with the experimental group.
ATAR Scientific Inquiry & Understanding 4
The term 'validity' in an experiment refers to: