Which of the following statements is not true of scientific experiments?

Question

They must be well documented.
They yield useful results regardless of whether the hypothesis is supported or rejected.
They must occur under carefully controlled conditions found in a laboratory.
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Part B
In an experiment, investigators try to control all of the variables except one—the one that tests the hypothesis. Which of the following reasons is the primary rationale for controlling variables in an experiment?
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To enable investigators to repeat the test
To create a control group
To eliminate alternative explanations for the results of an experiment
Part C
Which of the following statements could not be supported or rejected by a scientific experiment?
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College students think football is more fun to watch than baseball.
The first living cell on Earth came from outer space
Grass is green because it contains chlorophyll.
Part D
Which of the following statements is true of a hypothesis?
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A hypothesis can be proved.
A hypothesis can be supported or rejected through experimentation.
Part E
Which of the following variables did Pasteur change in his experiment to test the hypothesis of spontaneous generation?
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The shape of the flask
The length of time that the broth was boiled
The broth used in each flask
The length of time that the flasks were allowed to sit before being sampled for organisms
Part F
In Pasteur's experiment to test the hypothesis of spontaneous generation, why did he boil the broth in both flasks?
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To attract dust particles to each flask
To provide nutrients to stimulate the growth of microorganisms
To expose the broth to a source of organisms
To kill any existing organisms in the broth
Part G
Suppose the sub-hypothesis that wing waving alone reduces predation by jumping spiders was supported by the Zonosemata experiment. What results would have supported that sub-hypothesis?

Zonosemata flies with their own wings cut and reglued are attacked less frequently.
Houseflies with Zonosemata wings are attacked less frequently.
Untreated Zonosemata flies are attacked less frequently.
Zonosemata flies with housefly wings are attacked less frequently.
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Part H
Suppose that Zonosemata flies whose own wings had been clipped and reattached were attacked more frequently than untreated Zonosemata flies. How would this result have affected the reliability of the other experimental results?

All results for the experimental groups using houseflies would be invalid.
All results for the experimental groups involving wing surgery would be invalid.
The reliability of the experimental results would not change.
All results for the experimental groups using Zonosemata flies would be invalid.

Answer 1

Part A:
Which of the following statements is not true of scientific experiments?

• They must occur under carefully controlled conditions found in a laboratory. (This statement is not necessarily true as scientific experiments can occur in various settings, including field studies.)

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Part B:
In an experiment, investigators try to control all of the variables except one—the one that tests the hypothesis. Which of the following reasons is the primary rationale for controlling variables in an experiment?

• To eliminate alternative explanations for the results of an experiment. (This is the primary reason for controlling variables.)

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Part C:
Which of the following statements could not be supported or rejected by a scientific experiment?

• College students think football is more fun to watch than baseball. (This statement is subjective and cannot be definitively tested by a scientific experiment.)

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Part D:
Which of the following statements is true of a hypothesis?

• A hypothesis can be supported or rejected through experimentation. (This is the correct statement regarding a hypothesis.)

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Part E:
Which of the following variables did Pasteur change in his experiment to test the hypothesis of spontaneous generation?

• The shape of the flask. (This change helped determine whether microorganisms entered the broth from the air.)

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Part F:
In Pasteur's experiment to test the hypothesis of spontaneous generation, why did he boil the broth in both flasks?

• To kill any existing organisms in the broth. (Boiling was done to sterilize the broth and eliminate pre-existing life.)

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Part G:
Suppose the sub-hypothesis that wing waving alone reduces predation by jumping spiders was supported by the Zonosemata experiment. What results would have supported that sub-hypothesis?

• Untreated Zonosemata flies are attacked less frequently. (This result would support the idea that wing waving is effective in reducing predation.)

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Part H:
Suppose that Zonosemata flies whose own wings had been clipped and reattached were attacked more frequently than untreated Zonosemata flies. How would this result have affected the reliability of the other experimental results?

• All results for the experimental groups involving wing surgery would be invalid. (This would raise concerns about the validity of any results related to the treatment involving wing clipping and reattachment.)