1.
What is an independent variable in an experiment?
Correct Answer
B. What is varied
Explanation
An independent variable in an experiment is the one that the experimenter changes or manipulates to observe its effect on the dependent variable. By varying this variable, scientists can determine if it causes any changes in the outcome. For example, in testing a new drug, the dosage might be the independent variable to see its effect on patients' symptoms, which are the dependent variables.
2.
Which type of variable is manipulated to test its effects on another variable?
Correct Answer
C. Independent variable
Explanation
The independent variable is intentionally manipulated by the researcher to test its impact on the dependent variable, which is the variable being measured. For example, altering the light levels to see its effect on plant growth allows researchers to understand how light influences growth rates.
3.
What is a hypothesis in the context of scientific research?
Correct Answer
B. An educated guess
Explanation
A hypothesis in scientific research is an educated guess based on existing knowledge. It proposes a relationship between variables and is tested through experimentation. The hypothesis guides the design of the experiment by suggesting what results might be expected. It's crucial because it provides a focused direction for the research, hypothesizing potential outcomes that can be either confirmed or refuted by the experimental data.
4.
In a plant growth experiment, what is the dependent variable?
Correct Answer
C. Height of the plant
Explanation
A hypothesis in scientific research is an educated guess based on existing knowledge. It proposes a relationship between variables and is tested through experimentation. The hypothesis guides the design of the experiment by suggesting what results might be expected. It's crucial because it provides a focused direction for the research, hypothesizing potential outcomes that can be either confirmed or refuted by the experimental data.
5.
What does a controlled variable refer to?
Correct Answer
B. Is kept the same
Explanation
A controlled variable refers to elements that are not changed throughout the experiment and are kept constant to ensure that the test conditions are the same for all subjects or samples. This ensures that the observed effects on the dependent variable are solely due to the manipulation of the independent variable, providing valid and reliable results.
6.
Which variable is measured at the end of an experiment?
Correct Answer
C. Dependent variable
Explanation
The dependent variable is what researchers measure in an experiment and what they expect to change as a result of the manipulation of the independent variable. For instance, if examining the effect of different fertilizers on plant growth, the growth of the plants is the dependent variable that is measured at the conclusion of the study.
7.
What is the primary purpose of setting a hypothesis in an experiment?
Correct Answer
C. To guide the experiment
Explanation
The primary purpose of setting a hypothesis in an experiment is to establish a basis for the experiment that is testable and falsifiable. It directs the research process by suggesting potential outcomes and implications, which helps in structuring the study design and methodology, ultimately guiding the analytical process to interpret the results.
8.
If a scientist keeps the temperature constant in a plant experiment, this is an example of which type of variable?
Correct Answer
D. Controlled
Explanation
Keeping the temperature constant in an experiment classifies it as a controlled variable because it is an environmental condition that the researcher decides not to change. This ensures that any observed effects can be attributed to the variables being tested, such as light or water, rather than external temperature fluctuations.
9.
What type of hypothesis is formulated to be disproven through testing?
Correct Answer
A. Null hypothesis
Explanation
A null hypothesis is formulated specifically to be disproven or rejected through testing. It states that there is no statistical significance between the specified variables, and any correlation observed in the experiment results from chance. The purpose of the null hypothesis is to provide an objective benchmark against which the actual experimental results are compared.
10.
In a reaction time study, if the hypothesis is that caffeine reduces reaction time, what is caffeine considered?
Correct Answer
C. Independent variable
Explanation
In a reaction time study where the hypothesis posits that caffeine reduces reaction time, caffeine is considered the independent variable because it is the condition being manipulated. The experiment would vary caffeine intake among participants to observe how it affects their reaction times, making caffeine the variable that influences the dependent variable.