A researcher measured the heart rates of 20 male athletes and 20 female athletes before and immediately after 30 minutes of continuous strenuous exercise. The strenuous exercise included running for 15 minutes and bicycling for 15 minutes. The researcher recorded the data in the table.
Which statement is a valid conclusion from the data?
- A. The male athletes used more energy than the female athletes after 30 minutes of exercise.
- B. Strenuous exercise is more difficult for male athletes than female athletes.
- C. The average increase in heart rate was lower for the females than for the males.
- D. All the females had a lower heart rate than the males after 30 minutes of exercise.
Correct Answer & Rationale
Correct Answer: C
Option C accurately reflects the data, indicating a measurable difference in heart rate between male and female athletes after 30 minutes of exercise. This conclusion is supported by the data trends, which typically show a higher average heart rate in males. Option A makes an assumption about energy expenditure without specific data to support it, making it invalid. Option B incorrectly suggests a subjective comparison of difficulty, which cannot be deduced from heart rate data alone. Lastly, Option D overgeneralizes by claiming that all females had lower heart rates than males, which is unlikely and not supported by typical statistical findings, as individual variations exist.
Option C accurately reflects the data, indicating a measurable difference in heart rate between male and female athletes after 30 minutes of exercise. This conclusion is supported by the data trends, which typically show a higher average heart rate in males. Option A makes an assumption about energy expenditure without specific data to support it, making it invalid. Option B incorrectly suggests a subjective comparison of difficulty, which cannot be deduced from heart rate data alone. Lastly, Option D overgeneralizes by claiming that all females had lower heart rates than males, which is unlikely and not supported by typical statistical findings, as individual variations exist.
Other Related Questions
What natural process is required to connect the ice core data to the Tunguska Event?
- A. the cycling of carbon in forest fires
- B. the interaction of comets with the solar wind
- C. the movement of glaciers due to gravity
- D. the constant mixing of the atmosphere
Correct Answer & Rationale
Correct Answer: D
Connecting ice core data to the Tunguska Event necessitates understanding atmospheric dynamics, which is achieved through the constant mixing of the atmosphere. This mixing disperses particles and gases, allowing researchers to correlate ice core samples with historical events, including the Tunguska explosion. Option A, the cycling of carbon in forest fires, is unrelated to the atmospheric conditions or the specific data derived from ice cores. Option B, the interaction of comets with the solar wind, pertains to space phenomena rather than terrestrial atmospheric processes. Option C, the movement of glaciers due to gravity, describes glacial dynamics but does not address the atmospheric mixing needed to link ice core data to the event.
Connecting ice core data to the Tunguska Event necessitates understanding atmospheric dynamics, which is achieved through the constant mixing of the atmosphere. This mixing disperses particles and gases, allowing researchers to correlate ice core samples with historical events, including the Tunguska explosion. Option A, the cycling of carbon in forest fires, is unrelated to the atmospheric conditions or the specific data derived from ice cores. Option B, the interaction of comets with the solar wind, pertains to space phenomena rather than terrestrial atmospheric processes. Option C, the movement of glaciers due to gravity, describes glacial dynamics but does not address the atmospheric mixing needed to link ice core data to the event.
If these results correctly predict the performance of this kneepad design, what is the probability that one of the kneepads will require a force of 145 N or greater to cause failure?
- A. 53%
- B. 22%
- C. 75%
- D. 25%
Correct Answer & Rationale
Correct Answer: D
To determine the probability of a kneepad requiring a force of 145 N or greater to cause failure, we analyze the data provided. The correct option, 25%, indicates that one-fourth of the kneepads are expected to fail under this force, aligning with statistical predictions for this design. Option A (53%) overestimates the likelihood, suggesting more than half will fail, which is not supported by the data. Option B (22%) underestimates the probability, indicating fewer kneepads will fail than expected. Option C (75%) is excessively high, implying a significant majority would fail, which contradicts the predicted performance. Thus, 25% accurately reflects the failure rate at this force threshold.
To determine the probability of a kneepad requiring a force of 145 N or greater to cause failure, we analyze the data provided. The correct option, 25%, indicates that one-fourth of the kneepads are expected to fail under this force, aligning with statistical predictions for this design. Option A (53%) overestimates the likelihood, suggesting more than half will fail, which is not supported by the data. Option B (22%) underestimates the probability, indicating fewer kneepads will fail than expected. Option C (75%) is excessively high, implying a significant majority would fail, which contradicts the predicted performance. Thus, 25% accurately reflects the failure rate at this force threshold.
According to the passage, which statement about hybrid lovebirds is true?
- A. Nest-building behavior can be used to determine evolutionary relationships between lovebird species.
- B. Hybrid lovebirds use nest-building material in ways they learn from the parents.
- C. Nest-building behavior in hybrid lovebirds is a mixture of the parents' behaviors.
- D. Hybrid lovebirds build complex nests using smaller pieces of nest-building material.
Correct Answer & Rationale
Correct Answer: C
Hybrid lovebirds exhibit nest-building behavior that reflects a combination of their parents' distinct styles, showcasing the influence of both species in their hybrid traits. This blending of behaviors illustrates how hybridization can lead to unique adaptations. Option A is incorrect as the passage does not indicate that nest-building behavior is a reliable indicator of evolutionary relationships. Option B is misleading; while learning from parents is important, the focus is on the integration of behaviors rather than direct imitation. Option D is inaccurate; the passage does not mention the complexity of nests or the size of materials used, making this statement unsupported.
Hybrid lovebirds exhibit nest-building behavior that reflects a combination of their parents' distinct styles, showcasing the influence of both species in their hybrid traits. This blending of behaviors illustrates how hybridization can lead to unique adaptations. Option A is incorrect as the passage does not indicate that nest-building behavior is a reliable indicator of evolutionary relationships. Option B is misleading; while learning from parents is important, the focus is on the integration of behaviors rather than direct imitation. Option D is inaccurate; the passage does not mention the complexity of nests or the size of materials used, making this statement unsupported.
What statement describes one or more needed changes to this experiment that would allow the experimenter to draw a valid conclusion?
- A. Salt water should have been used to make the ice cubes for the cup of salt water.
- B. The time for ice cubes to melt should have been measured in minutes.
- C. At the beginning, both cups should have contained the same mass of water at the same temperature.
- D. The energy released should have been measured, not calculated.
Correct Answer & Rationale
Correct Answer: C
Option C highlights the necessity for both cups to start with the same mass of water at the same temperature to ensure a fair comparison. This control eliminates variables that could skew results, allowing for a valid conclusion about the melting rates of ice cubes in different solutions. Option A is incorrect because using salt water to make ice cubes would not provide relevant data on how the ice behaves in fresh versus salt water. Option B is not a change that affects the experimental validity; measuring time in minutes is appropriate, but the key is ensuring conditions are equal. Option D suggests a measurement method change, but calculating energy based on temperature changes is acceptable in this context.
Option C highlights the necessity for both cups to start with the same mass of water at the same temperature to ensure a fair comparison. This control eliminates variables that could skew results, allowing for a valid conclusion about the melting rates of ice cubes in different solutions. Option A is incorrect because using salt water to make ice cubes would not provide relevant data on how the ice behaves in fresh versus salt water. Option B is not a change that affects the experimental validity; measuring time in minutes is appropriate, but the key is ensuring conditions are equal. Option D suggests a measurement method change, but calculating energy based on temperature changes is acceptable in this context.