Question 1

Which of the following best describes the purpose of a null hypothesis ($$H_0) in $$scientific experiments?

Accepted Answer

To state that changing the independent variable will not affect the dependent variable.

Question 2

In the kelp acidification experiment, which variable is manipulated by the researcher?

Accepted Answer

The pH of seawater

Question 3

Which statement is an example of an alternative hypothesis ($$H_A$$)?

Accepted Answer

"Reducing the pH of seawater will reduce the growth rate of kelp."

Question 4

Why is replication important in scientific studies?

Accepted Answer

It improves the repeatability and reliability of measurements and results.

Question 5

Which of the following is a feature of a good experimental study?

Accepted Answer

Using standardized methods and proper controls.

Question 6

In an observational study, what does a correlation between two variables indicate?

Accepted Answer

That the variables change together, but causation is not established.

Question 7

A researcher wants to test the effect of fertilizer on plant growth. Which is the dependent variable?

Accepted Answer

The growth of the plants measured over time

Question 8

Which of the following best explains why scientists use models to test hypotheses?

Accepted Answer

Models can represent how a system works and predict outcomes based on inputs.

Question 9

If a model's output matches historical data, what conclusion can be drawn?

Accepted Answer

The hypothesis represented by the model is supported for the tested conditions.

Question 10

Which of the following is an example of a confounding variable in an experiment testing the effect of light on plant growth?

Accepted Answer

The amount of water each plant receives

Question 11

A scientist conducts an experiment with two groups: one receives a new drug, and the other receives a placebo. What is the purpose of the placebo group?

Accepted Answer

To serve as a control group for comparison.

Question 12

Which of the following statements about observational studies is TRUE?

Accepted Answer

They can show correlation but not causation.

Question 13

In the context of hypothesis testing, what does it mean to 'reject the null hypothesis'?

Accepted Answer

The results support the alternative hypothesis.

Question 14

Which of the following is NOT a main way to test hypotheses in science?

Accepted Answer

Anecdotal evidence

Question 15

A scientist wants to know if kelp growth is affected by ocean acidification. Which is the best way to set up the experiment?

Accepted Answer

Manipulate the pH of seawater and measure kelp growth in both experimental and control groups.

Question 16

Which equation correctly represents the relationship between independent and dependent variables in a model?

Accepted Answer

$$Output = Model(Input)$$

Question 17

Why is it important to randomly assign individuals to control and experimental groups?

Accepted Answer

To ensure that confounding variables are evenly distributed between groups.

Question 18

Which of the following is a reason to use observational studies even though they do not prove causation?

Accepted Answer

They can verify experimental results in real-world settings.

Question 19

A scientist finds a strong correlation between ice cream sales and drowning incidents. What is the most likely explanation?

Accepted Answer

There is a spurious correlation due to a third variable, such as temperature.

Question 20

Which of the following best describes the process of making a prediction based on a hypothesis?

Accepted Answer

Stating what you expect to happen if the hypothesis is correct, often using an 'If...then...' statement.

Science as a Way of Knowing: Forming and Testing Hypotheses

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