Multiple Choice

1. What is the initial, testable prediction or educated guess made before conducting a scientific experiment?

   Scientific Law

   Observation

   Hypothesis

   Conclusion

2. In an experiment investigating how fertilizer affects plant height, which factor is the independent variable?

   The amount of fertilizer applied.

   The measured height of the plants.

   The amount of water given to the plants.

   The type of soil used.

3. Which type of variable is the factor that the scientist measures or observes as a result of the experiment?

   Dependent Variable

   Controlled Variable

   Extraneous Variable

   Independent Variable

4. Why must controlled variables (constants) be kept the same across all groups in an experiment?

   To ensure the hypothesis is always proven true.

   To make the experiment easier to set up.

   To ensure only the independent variable causes changes in the dependent variable.

   To increase the total number of test subjects.

5. A student wants to test if warmer water dissolves sugar faster. What is the dependent variable in this experiment?

   The amount of sugar used.

   The type of container used.

   The time it takes for the sugar to dissolve.

   The temperature of the water.

6. The first step in the scientific method is usually:

   Conducting an experiment.

   Making observations and asking a question.

   Analyzing data.

   Forming a hypothesis.

7. If a researcher studies the effect of sleep deprivation on test scores, 'test scores' represents which variable?

   Environmental Variable

   Dependent Variable

   Independent Variable

   Controlled Variable

8. What term describes the factors in an experiment that are intentionally kept the same to maintain fairness?

   Extraneous Variables

   Manipulated Variables

   Result Variables

   Controlled Variables

9. A hypothesis is often written in the format: "If [Independent Variable change], then [Dependent Variable response]." This structure emphasizes:

   The conclusion drawn from the study.

   Correlation without causation.

   The relationship between cause and effect.

   Detailed data analysis.

10. In an experiment testing if light color affects plant growth, factors like the species of plant, the pot size, and the duration of light exposure are examples of:

    Dependent variables.

    Controlled variables.

    Independent variables.

    Experimental variables.

11. What is the primary purpose of conducting a controlled experiment?

    To test the effect of a single independent variable on a dependent variable.

    To gather as much data as possible, regardless of accuracy.

    To establish correlation between any two variables.

    To prove a scientific law is incorrect.

12. Experimental validity refers to:

    The complexity of the procedures used.

    Whether the experiment can be completed quickly.

    How many times the experiment was repeated.

    Whether the results genuinely reflect the relationship between the variables being tested.

13. Which action is crucial for maintaining the internal validity of an experiment?

    Allowing different environmental conditions for different groups.

    Changing the hypothesis halfway through the study.

    Controlling all extraneous factors that might influence the results.

    Using a very small sample size.

14. What is an "extraneous factor" in the context of a controlled experiment?

    A variable other than the independent variable that could potentially affect the results.

    The main variable being tested.

    Variables that are intentionally kept constant.

    The measurable result of the experiment.

15. Why is repetition (replication) important for the validity of an experimental conclusion?

    It guarantees the hypothesis is always supported.

    It reduces the likelihood of ethical concerns.

    It ensures that the conclusion is complex enough.

    It confirms that the initial results were not due to chance or error.

16. A lab procedure requires all liquid measurements to be done with a graduated cylinder. If one group uses a beaker instead, this compromises the experiment's:

    Hypothesis formation.

    Data charting.

    Validity.

    Conclusion synthesis.

17. The term "experimental group" refers to the group in a controlled experiment that:

    Receives the specific treatment being tested (the independent variable).

    Is the standard against which comparisons are made.

    Only has controlled variables applied to it.

    Receives no treatment or manipulation.

18. If an experiment lacks validity, what does that imply about its findings?

    The findings are too complex to understand.

    The findings are easily replicated by others.

    The findings are definitely false.

    It is difficult to determine if the independent variable was truly responsible for the observed results.

19. Which characteristic defines a well-designed controlled experiment?

    It tests multiple independent variables simultaneously.

    It incorporates complex mathematical models.

    It uses qualitative data exclusively.

    It isolates and manipulates only one independent variable at a time.

20. To ensure the results are trustworthy (valid), scientists must primarily focus on:

    Maximizing control over experimental conditions.

    Using the most expensive equipment available.

    Writing a clear lab report.

    Selecting the largest possible sample size.

21. What is the primary function of a control group in a controlled experiment?

    To provide a standard baseline for comparison.

    To test the effect of the dependent variable on the independent variable.

    To serve as a second experimental group to increase sample size.

    To receive the highest possible dose of the independent variable.

22. How is the control group typically treated regarding the independent variable?

    It receives no treatment or a neutral/placebo treatment.

    It receives varying levels of the independent variable.

    It is treated differently than the experimental group in every way.

    It receives the maximum amount of the independent variable.

23. Imagine testing a new drug. The control group would most likely receive:

    A non-drug substance that looks identical (a placebo).

    A harmless substance with no active ingredients.

    Half the dose of the new drug being tested.

    A higher dose of the old, existing drug.

24. If an experimental group shows a significant increase in growth after receiving a fertilizer, how does the control group help interpret this result?

    It shows how much the dependent variable decreased due to the fertilizer.

    It demonstrates the effect of the soil type on growth.

    It confirms that the independent variable works on all plants.

    It shows how much the plants grew naturally without the fertilizer.

25. Why is a control group considered necessary rather than optional for establishing causation?

    It helps formulate the hypothesis after the experiment.

    It guarantees that all controlled variables are effective.

    Without it, the experiment cannot be repeated.

    It allows the researcher to attribute changes solely to the independent variable.

26. If the experimental group and the control group both show the same level of change in the dependent variable, what can the researcher conclude?

    The hypothesis was proven correct.

    The experiment was invalid due to too many controlled variables.

    The independent variable likely had no effect.

    The independent variable had a strong, positive effect.

27. A control group and an experimental group must be identical in every way EXCEPT:

    The constant (controlled) factors.

    The dependent variable measurement.

    The application of the independent variable.

    The location where the experiment is performed.

28. Suppose a student tests a new brand of batteries. The control group should be the batteries:

    That last the shortest amount of time.

    Already commonly used or a standard baseline brand.

    That are used in a completely different device.

    That are manufactured by the student.

29. The comparison between the control group and the experimental group ultimately helps the scientist:

    Determine the budget required for future studies.

    Determine if the change observed is statistically meaningful.

    Generate a list of all potential extraneous variables.

    Formulate entirely new hypotheses.

30. If a scientist forgets to include a control group, the experiment loses its ability to:

    Maintain controlled variables.

    Isolate the cause-and-effect relationship.

    Define the independent variable.

    Measure the dependent variable.

31. Design Scenario: A student investigates whether playing music (Independent Variable) affects the speed at which mice complete a maze (Dependent Variable). To ensure validity, which factor must be kept constant?

    The speed at which the mice run.

    The complexity of the dependent variable.

    The specific type and layout of the maze.

    The time of day the music is played.

32. Synthesis Question: Which combination of components is essential for maximizing the validity of a controlled experiment?

    A control group, constant controlled variables, and isolation of the independent variable.

    Complex calculations and qualitative data.

    A vague hypothesis and a large sample size.

    Many extraneous variables and repeated trials.

33. If an experiment has too many uncontrolled extraneous variables, the results are likely to be:

    Highly reliable and easily repeatable.

    Clear and simple to analyze.

    Specific to only one experimental setup.

    Invalid and misleading.

34. A scientist decides to run an experiment testing three different temperatures on bacterial growth. How many control groups are required for this study?

    It depends on the size of the bacterial colonies.

    One, consisting of bacteria grown at a standard, established temperature (or room temp).

    Three, one for each temperature tested.

    Zero, as temperature is easy to measure.

35. Which statement best describes the relationship between controlled variables and validity?

    Maintaining controlled variables is necessary to establish internal validity.

    Controlled variables are only important when measuring the dependent variable.

    Uncontrolled variables increase validity by introducing randomness.

    Increasing controlled variables always decreases validity.

36. Assessment Question: A student tested if fertilizer X makes plants grow taller than fertilizer Y. The final conclusion was that X leads to taller plants. What must the student have used to confirm that both fertilizers actually increased growth compared to no treatment?

    A control group receiving only water and soil.

    A group that received fertilizer X and Y combined.

    A second dependent variable measurement.

    A placebo group receiving fake fertilizer.

37. What error in design would most severely threaten the external validity (generalizability) of an experiment?

    Running the experiment for too short a time period.

    Not measuring the dependent variable precisely enough.

    Using a sample population that is too small and non-representative.

    Conducting the experiment only once without replication.

38. When designing a proper procedure, the researcher must operationalize the variables, meaning they must:

    Focus on ethical implications only.

    Determine if the hypothesis is correlation or causation.

    Define exactly how the independent and dependent variables will be measured and manipulated.

    Explain the historical context of the research.

39. Synthesis: Why is data collected from the control group often considered the "baseline data"?

    Because it is used only to calculate the controlled variables.

    Because it must always show zero change.

    Because it is the fastest data to collect.

    Because it represents the natural or standard state without the experimental treatment.

40. The final stage of a scientific investigation involves comparing the experimental results against the initial hypothesis. If the results do not support the hypothesis, the scientist should:

    Change the results to fit the hypothesis.

    Conclude the experiment was completely useless.

    Discard all the collected data.

    Analyze the data, state the actual finding, and revise the hypothesis for future testing.

41. A researcher wants to test if "the amount of loud music played" (Independent Variable, IV) affects a person's "reaction time" (Dependent Variable, DV). To create a complete operational definition for the IV, the researcher must specify details that allow precise manipulation. Which option provides the most necessary operational detail for the IV?

    The participant’s subjective rating of how much they enjoyed the music.

    The type of musical instrument used for the experiment.

    The total number of errors made by the participant during the reaction time test.

    The exact decibel level (dB) of the music measured at the participant's ear and the duration it was played.

42. An operational definition for the Dependent Variable (DV) must detail how the variable will be measured and quantified. If a student wants to operationally define the DV "level of friendliness" in a study, which detail is essential for a strong definition?

    The abstract concept that explains why some people are friendly and others are not.

    The number of times the participant smiles and makes eye contact during a 5-minute standardized interaction with a stranger.

    The total number of hours of sleep the participants received before the study.

    The researcher’s prediction that people will be friendlier after drinking coffee.

43. Operational definitions are crucial because they ensure that a study is replicable. For a variable to be considered operationally defined, the procedures used to manipulate or measure it must meet which requirement?

    They must be concrete, observable, and quantifiable so other scientists can repeat the procedures exactly.

    They must align perfectly with the scientist’s hypothesis.

    They must explain the theoretical rationale behind the variable.

    They must be based on a large amount of historical data.

44. A scientist studies if "exposure to natural light" (IV) increases "worker productivity" (DV). The scientist proposes to define "worker productivity" as "the number of documents filed in one hour." What critical missing operational detail would need to be standardized to ensure the DV measurement is robust and fair?

    The specific criteria (e.g., complexity, length, necessary organization) for what constitutes a "filed document."

    The total amount of natural light available throughout the day.

    The type of windows installed in the office building.

    The average age of the workers participating in the study.

45. A Grade 9 student is testing if eating breakfast (IV) affects a student's "morning alertness" (DV). The student plans to operationally define the IV by comparing one group that eats "a full breakfast" to another group that eats "no breakfast." Which detail is required to make the IV (the breakfast condition) truly operational and standardized?

    Defining "a full breakfast" by specifying the specific foods and quantity of each item provided to the participants.

    The average grades the students received in their previous science class.

    The exact amount of energy (calories and macronutrients) consumed by the "full breakfast" group.

    The students' reported subjective feeling of alertness upon entering the classroom.