Godinez: In the past, land was sometimes measured by the amount of time required to plow it. Thus, two plots of equal physical dimensions were considered unequal if one was more difficult to plow than the other. However, knowing how long an area takes to plow reveals little about how many apartment complexes it can hold. Therefore, it became necessary to adopt new measures of land, such as acreage, when land uses diversified.

Summarize Argument
The author concludes that we needed to come up with new ways to measure the value of land when the uses to which the land was put became more diverse. As an example, if land is used for farming, then the time it takes to plow the land is relevant to the land’s value. But if the land is used for apartments, plow time isn’t useful.

Identify Conclusion
The conclusion is the author’s assessment of the need for a change in measurement of land value: “[I]t became necessary to adopt new measures of land ... when land uses diversified.”

A
It is now easier to measure a piece of land in terms of acres than in terms of plowing time.
The conclusion doesn’t assert anything about the ease or difficulty of measuring land value. It merely states that there was a need for new measures of land value.
B
For modern purposes, newer methods provide a more accurate measure of land than plowing time does.
This may be strongly supported by the argument, but it’s not the conclusion. The conclusion concerns how new measures are necessary. It’s not about the accuracy of particular measurements of land value.
C
Some plots of land that would have been considered unequal by plowing-time measurements are of equal physical dimensions.
This relates only to the context in the first two sentences. The author’s conclusion concerns the necessity of adopting new measures of value.
D
Modern measures of land were adopted when people realized that plowing time was an inadequate measure for some land uses.
This doesn’t capture the author’s claim in the conclusion that new measures were “necessary.” The author wasn’t just saying that modern measures were adopted after plowing-time became inadequate. He was also asserting that we were required to adopt new methods.
E
The advent of diversified land uses made new measures of land necessary.
This paraphrases the conclusion. The “advent of diversified land uses” matches with “when land uses diversified,” and “made new measures of land necessary” matches with “it became necessary to adopt new measures of land.”

12 comments

Researcher: Overhearing only one side of a cell-phone conversation diverts listeners’ attention from whatever they are doing. Hearing only part of a conversation leaves listeners constantly trying to guess what the unheard talker has just said. Listeners’ attention is also diverted because cell-phone talkers speak abnormally loudly.

Summary

Hearing only one side of a cell-phone conversation distracts a person from whatever they’re doing. Hearing only one person in a conversation results in listeners constantly trying to guess what the unheard person is saying. Cell-phone conversations distract listeners because people talking on a cell-phone are abnormally loud.

Strongly Supported Conclusions

When a person performing a task hears a cell-phone conversation, that person ends up distracted from whatever they’re doing.

A
The risk that a driver will cause an accident is increased when the driver is talking on a cell phone.

This answer is unsupported. We don’t know from the stimulus what the risk of accident is for any driver. Since we don’t know the baseline risk, we also can’t say that this risk increases.

B
When a driver hears a passenger in the driver’s vehicle talking on a cell phone, that detracts from the driver’s performance.

This answer is strongly supported. Hearing only one side of a cell-phone conversation distracts a person from whatever they’re doing. Since the driver is distracted, this detracts from their driving.

C
Overhearing one side of a conversation on a traditional telephone does not divert listeners’ attention from tasks at hand.

This answer is unsupported. The stimulus is limited to overhearing conversations being had over a cell-phone. We don’t know what the effects are from overhearing a conversation had over a traditional phone.

D
People who overhear one side of a cell-phone conversation inevitably lose track of their thoughts.

This answer is unsupported. We don’t know if these people lose track of their own thoughts, we just know that they become distracted from whatever they’re doing.

E
Conversing on a cell phone requires making more guesses about what one’s conversational partner means than other forms of conversation do.

This answer is unsupported. We don’t know what conditions are required for having a conversation via cell-phone.


22 comments

Farmer: Agricultural techniques such as crop rotation that do not use commercial products may solve agricultural problems at least as well as any technique, such as pesticide application, that does use such products. Nonetheless, no private for-profit corporation will sponsor research that is unlikely to lead to marketable products. Thus, for the most part, only government-sponsored research investigates agricultural techniques that do not use commercial products.

Summarize Argument
The author concludes that generally, only government-sponsored research investigates agricultural techniques that don’t use commercial products. This is based on the fact that private for-profit corporations don’t sponsor research that’s unlikely to lead to marketable products.

Notable Assumptions
The author assumes that agricultural techniques that don’t use commercial products are unlikely to lead to the creation of marketable products. The author also assumes that there’s no other source that could conduct research into agricultural techniques that don’t use commercial products besides private for-profit corporations and the government.

A
The government sponsors at least some investigations of agricultural techniques that are considered likely to solve agricultural problems and do not use commercial products.
This doesn’t help establish that only government-sponsored research investigates these techniques. (A) tells us that the government does at least some of this research, but we don’t know whether there could be other sources that also do this research.
B
For almost any agricultural problem, there is at least one agricultural technique that does not use commercial products but that would solve that agricultural problem.
This doesn’t help establish what kinds of entities research agricultural techniques and whether governments are the only ones who will research techniques that are unlikely to lead to marketable products.
C
Investigations of agricultural techniques are rarely sponsored by individuals or by any entity other than private for-profit corporations or the government.
This strengthens the argument by limiting the potential entities that conduct research to, in most cases, private for-profit corporations and the government. Since the premises already eliminate private corporations as a source of research, we’re left with the government.
D
Most if not all investigations of agricultural techniques that use commercial products are sponsored by private for-profit corporations.
The argument is concerned with research into techniques that don’t use commercial products. Which entities research the techniques that do use commercial products has no impact on the reasoning.
E
Most if not all government-sponsored agricultural research investigates agricultural techniques that do not use commercial products.
This doesn’t help show that research investigating agricultural techniques that don’t use commercial products is exclusively done by the government. (E) leaves open the possibility that non-government entities also do a lot of this research.

28 comments

Creating a database of all the plant species in the scientific record has proved to be no easy task. For centuries, botanists have been collecting and naming plants without realizing that many were in fact already named. And by using DNA analysis, botanists have shown that varieties of plants long thought to belong to the same species actually belong to different species.

Summary
Creating a database of all the plant species in the scientific record is not easy. For centuries, botanists have been naming plants without realizing that some were already named. Moreover, by using DNA analysis, botanists have shown that varieties of plants long thought to belong to the same species actually belong to different species.

Notable Valid Inferences
DNA analysis could inform botanists whether a plant species has been named.

A
Most of the duplicates and omissions among plant names in the scientific record have yet to be cleared up.
Could be true. The stimulus does not give us any information about the total number of duplicates and omissions in the scientific record. It is possible that most of these errors have not yet been fixed.
B
An accurate database of all the plant species in the scientific record can serve as an aid to botanists in their work.
Could be true. There is no information in the stimulus that contradicts the idea that an accurate database would be helpful.
C
Duplicates and omissions in the scientific record also occur in fields other than botany.
Could be true. The information in the stimulus is restricted to botany. It is possible that the same or similar errors occur in other fields.
D
Botanists have no techniques for determining whether distinct plant species have been given distinct names.
Must be false. The stimulus tells us that DNA analysis has shown what plants belong to what species. Therefore, DNA analysis is a technique that botanists could use to determine whether a plant species has been given a distinct name.
E
A person who consults the scientific record looking under only one of a plant’s names may miss available information about that plant.
Could be true. The stimulus tells us that botanists have been naming plants without realizing that some plants have already been named. If this is true, then it is possible that some information about the same plant is just associated with a different name.

19 comments