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Experimental Design Practice Test — Medium Level

A free 10-question Experimental Design practice test for Science Olympiad, written at regional and state level. Every question and answer choice is listed below — correct answers and scoring are revealed when you take the timed test.

10 questions15 min timedMedium levelAI-generated — verify answers against reliable sources
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1. A student investigates how the concentration of salt in water affects the time it takes for an ice cube to melt. Which variable is the dependent variable in this experiment?

  • A.A) Volume of water used in each trial
  • B.B) Concentration of salt in the water
  • C.C) Time for the ice cube to melt
  • D.D) Temperature at which water freezes

2. In an experiment testing the effect of light color on plant growth, the control group should most appropriately be exposed to:

  • A.A) No light at all, to remove any light effects
  • B.B) The light color that is hypothesized to produce the greatest growth
  • C.C) A standard white light condition that represents normal growth conditions
  • D.D) Randomly changing light colors each day to average out the effects

3. A team measures the mass of a 50.0 g calibration weight five times and obtains: 44.8 g, 45.0 g, 44.9 g, 44.8 g, 44.9 g. Which statement best describes their data?

  • A.A) High accuracy and high precision
  • B.B) High accuracy and low precision
  • C.C) Low accuracy and high precision
  • D.D) Low accuracy and low precision

4. A researcher finds that as the number of hours students spend playing video games per week increases, their average test scores decrease. The correlation is statistically significant (p < 0.05). Which conclusion is most appropriate?

  • A.A) Playing video games causes students to perform worse on tests
  • B.B) Students who perform worse on tests are more likely to play video games
  • C.C) There is a relationship between video game time and test scores, but causation is not proven
  • D.D) There is no meaningful relationship because correlation cannot be used in experimental design

5. Which scenario best illustrates a systematic error?

  • A.A) A balance that is incorrectly zeroed reads 0.5 g too high for every measurement
  • B.B) A student occasionally misreads the meniscus, sometimes high and sometimes low
  • C.C) Small air currents randomly alter the period of a swinging pendulum
  • D.D) Slight differences in reaction time when using a stopwatch over many trials

6. A team tests whether fertilizer type affects plant height. They use three fertilizer types and a no-fertilizer group, all with the same plant species, soil, pot size, and watering schedule. Which statement best identifies the variables?

  • A.A) Independent variable: plant height; Dependent variable: fertilizer type
  • B.B) Independent variable: fertilizer type; Dependent variable: plant height
  • C.C) Independent variable: plant species; Dependent variable: soil type
  • D.D) Independent variable: watering schedule; Dependent variable: fertilizer type

7. A student collects the following data for the number of seeds germinated in five identical petri dishes: 18, 20, 20, 25, 27. What are the mean and median of this data set?

  • A.A) Mean = 20, Median = 20
  • B.B) Mean = 22, Median = 20
  • C.C) Mean = 22, Median = 22
  • D.D) Mean = 21, Median = 20

8. Which hypothesis is best written for an experiment on how temperature affects the rate at which sugar dissolves in water?

  • A.A) Sugar dissolves in water because it is soluble
  • B.B) If the type of sugar is changed, then the rate of dissolving will change
  • C.C) If the temperature of the water increases, then sugar will dissolve faster because higher temperature increases molecular motion
  • D.D) If more sugar is added to the water, then the solution will become more concentrated

9. Two groups test the effect of pH on enzyme activity. Group 1 uses 5 trials per pH level; Group 2 uses 20 trials per pH level. Both find similar mean reaction rates. Which statement about their results is most accurate?

  • A.A) Group 1’s results are more reliable because they used fewer trials and had fewer chances for error
  • B.B) Group 2’s results are more reliable because a larger sample size generally reduces the impact of random error
  • C.C) Both groups’ results are equally reliable because the means are similar
  • D.D) Group 1’s results are more reliable because they likely finished faster and reduced time-related variables

10. A data set from an experiment has a mean of 50 units and a small standard deviation. Which interpretation is most consistent with this information?

  • A.A) Most data points are close to 50, indicating low variability among trials
  • B.B) Most data points are far from 50, indicating high variability among trials
  • C.C) The experiment must have large systematic error affecting all trials
  • D.D) The sample size must be too small to draw any meaningful conclusions

Questions are AI-generated for Experimental Design practice and can contain mistakes — check answers against reliable sources. Take the timed version to see correct answers, scoring, and explanations: start the Experimental Design test.