Sign up to star your favorites LSAT 140 - Section 3 - Question 17
January 19, 2014Science teacher: In any nation, a flourishing national scientific community is essential to a successful economy. For such a community to flourish requires that many young people become excited enough about science that they resolve to become professional scientists. Good communication between scientists and the public is necessary to spark that excitement.
Summary
If a nation has a successful economy, it must have a flourishing national scientific community. If the nation has a flourishing national community, it needs to have many young people who are excited enough about science to want to become scientists. If this excitement exists, there must be good communication between scientists and the public.
Strongly Supported Conclusions
Successful economy -> flourishing scientific community -> young people excited - > good communication between scientists and the public.
You can make any valid inference along this chain.
A
If scientists communicate with the public, many young people will become excited enough about science to resolve to become professional scientists.
Scientists communicating with the public is not a sufficient condition that can trigger any valid inferences. If you got this wrong, practice conditional indicators, mapping, and following lawgic chains.
B
The extent to which a national scientific community flourishes depends principally on the number of young people who become excited enough about science to resolve to become professional scientists.
While young people's excitement about science is necessary for a national scientific community to flourish, there is no evidence that *the number* of these students is principally important.
C
No nation can have a successful economy unless at some point scientists have communicated well with the public.
This is supported because it is a valid inference on the formal logic chain (Successful economy -> good communication). If you struggled to map this, practice mapping with two conditional indicators.
D
It is essential to any nation’s economy that most of the young people in that nation who are excited about science become professional scientists.
This is too strong to support. The stimulus only says that many young people need to be excited about science, not “most.”
E
An essential component of success in any scientific endeavor is good communication between the scientists involved in that endeavor and the public.
This is not supported because the stimulus never gives conditions for the success of any scientific endeavor.
Sign up to star your favorites LSAT 140 - Section 3 - Question 16
January 19, 2014
Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that susnpot activity is probably a causal factor in the size of hare populations. This is because the hare population cycle between larger and smaller sizes is correlated with the regular cycle of sunspot activity.
Notable Assumptions
The author assumes that the correlation between sunspot activity and hare population cycles isn’t just coincidence.
A
Reproduction in predator populations increases when sunspot activity indirectly affects hormonal processes associated with reproduction.
This strengthens by providing a potential causal mechanism between sunspots and hare populations. The sunspots might affect predator populations, and the predator populations would in turn affect hare populations.
B
Local weather patterns that can affect species’ population changes can occur both in the presence of sunspot activity and in its absence.
This doesn’t strengthen because it doesn’t provide any reason to think the sunspot activity has any causal relationship with hare populations. We have no reason to think these weather patterns are correlated with sunspots.
C
Brighter light during sunspot activity subtly but significantly improves the ability of predators to detect and capture hares.
This strengthens by providing a causal mechanism between sunspots and hare populations. The sunspots can affect predator ability to hunt, which in turn affects hare populations.
D
The variation from cycle to cycle in the magnitude of the highs and lows in snowshoe hare populations is highly correlated with variations from cycle to cycle in the intensity of highs and lows in sunspot activity.
This strengthens by strengthening the correlation between sunspots and hare populations. Not only are these two things generally correlated, but (D) now tells us that the specific degree of population increase/decrease is correlated with the degree of sunspot intensity.
E
Sunspot activity is correlated with increases and decreases in the nutritional value of vegetation eaten by the hares.
This strengthens by providing a potential causal mechanism. Sunspots may have an effect on the nutritional value of vegetation, which in turn can affect hare populations that eat the vegetation.
Sign up to star your favorites LSAT 140 - Section 3 - Question 15
January 19, 2014Sign up to star your favorites LSAT 140 - Section 3 - Question 13
January 19, 2014
Summary
A group of 3-year-olds who new the numbers 1 through 10 were trying to learn their phone numbers. Initially no child could remember his or her number. But after a teacher taught each child a song that contained his or her phone number, the children could remember the phone number.
Strongly Supported Conclusions
The song the teacher taught probably helped each child remember his or her number.
A string of numbers might be easier to remember if they are part of a song.
A string of numbers might be easier to remember if they are part of a song.
A
There are some things that children cannot learn without the aid of songs.
Unsupported. Although the song likely helped the children remember their numbers, that doesn’t mean the song was required in order for them to remember. Maybe the children also could have remembered the numbers through a special game or special cartoon.
B
Familiarity with a concept is not always sufficient for knowing the words used to express it.
Unsupported. The children knew the numbers 1 through 10. There’s no evidence that they didn’t know the words to express these numbers. They had trouble remembering a specific string of numbers; not with the words that express those numbers.
C
Mnemonic devices such as songs are better than any other method for memorizing numbers.
Unsupported. The song likely helped them remember their phone numbers. But we don’t get a comparison to other memory methods. Maybe seeing the number in a special cartoon would have been more effective.
D
Children can learn to count without understanding the meaning of numbers.
Unsupported. Failing to remember a string of numbers does not imply inability to understand the meaning of numbers. We don’t have any evidence the children didn’t understand the meaning of “three.” They just had trouble remembering the order of several numbers put together.
E
Songs are useful in helping children remember the order in which familiar words occur.
Strongly supported. Children were familiar with individual numbers, but had trouble remembering a string of numbers. They were able to remember the string after learning a song containing that string of numbers. Doesn’t guarantee causation, but it is evidence the song helped.
Sign up to star your favorites LSAT 140 - Section 3 - Question 12
January 19, 2014
Summarize Argument
Heavier cans of fruit or vegetables from different companies may not actually contain more food. Some cans might have less food despite being heavier because the fruits and vegetables are packed in water, which can make up more than half the weight. Since some canning companies might add more water than others, heavier cans might not contain more food.
Identify Conclusion
The conclusion is the consumer advocate’s warning that heavier cans of fruit or vegetables may not actually contain more food.
A
The heavier of two cans of fruit or vegetables does not necessarily contain more food than the lighter of the two cans contains.
This accurately states the consumer advocate's main conclusion. Since packing companies can add more water to their cans, a heavier can of fruit or vegetables doesn’t always have more food than a lighter one. The heavier can might just have much more water than the lighter can.
B
The weight of the water in a can of fruit or vegetables can be more than half the total weight of the can’s contents.
This is a premise. The statement that water can make up more than half the weight of a can of fruit or vegetables helps readers understand the consumer advocate's conclusion that heavier cans don't always contain more food—they might just have more water.
C
Nothing stops unscrupulous canning companies from including more water per can than others include.
This is a premise. The claim that "nothing stops unscrupulous canning companies from including more water per can" supports the consumer advocate's conclusion that heavier cans do not always contain more food. The extra weight could just be from more water, not more food.
D
Some canning companies include less food in cans of a given weight than others include.
This is a necessary assumption of the consumer advocate’s argument. The advocate assumes that some canning companies might add more water and, therefore, less food to their cans. If this assumption is true, then a heavier can could have less food than another can of the same weight.
E
The heavier of two cans of fruits or vegetables may include more water than the lighter of the two cans contains.
This is a necessary assumption of the consumer advocate’s argument. The argument relies on the assumption that a heavier can may include more water—and therefore less food—than a lighter can. If this is true, then a heavier can doesn’t necessarily contain more food.
Sign up to star your favorites LSAT 140 - Section 3 - Question 11
January 19, 2014
Summary
The conclusion is that if broad mastery isn’t achieved, it must be that the students aren’t taught with appropriate methods. As support, the author gives a conditional premise: appropriate methods, combined with significant effort, lead to broad mastery. (Contrapositive: if broad mastery isn’t achieved, there either weren’t appropriate methods or there wasn’t significant effort.)
Missing Connection
The premise says that a lack of broad mastery means one of two things: a lack of appropriate methods or a lack of significant effort. But the conclusion is that broad mastery means one thing only: a lack of appropriate methods.
The conclusion would follow if we assumed that when there’s a lack of significant effort, there must also be a lack of appropriate methods. In that case, no matter what, a lack of broad mastery always means a lack of appropriate methods.
The conclusion would follow if we assumed that when there’s a lack of significant effort, there must also be a lack of appropriate methods. In that case, no matter what, a lack of broad mastery always means a lack of appropriate methods.
A
As long as secondary school students are taught with methods appropriate to their learning styles, they will devote significant effort to their studies.
Contrapositive: if students don’t devote significant effort, it must be that they’re not taught with appropriate methods. This means that no matter what, a lack of broad mastery means that student’s aren’t being taught with appropriate methods.
B
Even if secondary school students are taught with methods appropriate to their learning styles, they will not achieve broad mastery of the curriculum if they do not devote significant effort to their studies.
This says a lack of significant effort is sufficient for a lack of broad mastery. But this doesn’t change the argument’s core problem: a lack of broad mastery can mean either a lack of appropriate methods or a lack of significant effort. We’re still no closer to the conclusion.
C
Secondary school students do not achieve broad mastery of the curriculum if they are not taught with methods appropriate to their learning styles.
This says a lack of appropriate methods is sufficient for a lack of broad mastery. But this doesn’t change the argument’s core problem: a lack of broad mastery can mean either a lack of appropriate methods or a lack of significant effort. We’re still no closer to the conclusion.
D
Teaching secondary school students with methods appropriate to their learning styles does not always result in broad mastery of the curriculum by those students.
This breaks the argument. If appropriate methods aren’t sufficient for broad mastery, then the author can’t possibly conclude that a lack of broad mastery always implies a lack of appropriate methods.
E
Secondary school students who devote significant effort to their studies do not always achieve broad mastery of the curriculum.
So significant effort isn’t sufficient on its own for broad mastery. This doesn’t affect the argument, which says significant effort is sufficient if combined with appropriate methods. It’s still possible a lack of broad mastery sometimes implies a lack of significant effort.
Sign up to star your favorites LSAT 140 - Section 3 - Question 10
January 19, 2014Company president: Whenever you subcontract the manufacturing of a product, you lose some control over the quality of that product. We do subcontract some manufacturing, but only with companies that maintain complete control over the quality of the products they supply.
Summary
Company president:
Subcontracting manufacturing means losing some control over product quality.
We do subcontract some manufacturing.
We only subcontract with companies that have complete control over the quality of their products.
Very Strongly Supported Conclusions
The president’s company loses some control over its product quality.
The company’s subcontractors do not lose any control over their product quality.
The company’s subcontractors do not subcontract their manufacturing.
A
When the president’s company subcontracts manufacturing of a product, it does not allow the subcontractor to further subcontract manufacturing of that product.
Very strongly supported. Subcontracting manufacturing means losing some control over product quality. But the company’s subcontractors “maintain complete control over the quality of the products they supply.” So the subcontractors must not further subcontract their manufacturing.
B
Companies that subcontract the manufacturing of products are often disappointed in the quality of those products.
Unsupported. Subcontracting manufacturing reduces control over product quality, but it doesn't necessarily mean lower quality. It also doesn’t mean that companies will be disappointed with the quality of products that have been manufactured by a subcontractor.
C
The company president insists on having as much control as possible over the quality of the company’s products.
Anti-supported. Subcontracting manufacturing means losing some control over product quality. Since the company president subcontracts some manufacturing, he likely doesn’t insist on having as much control as possible over product quality.
D
When consumers know that a product has been manufactured by a subcontractor, they are generally dubious about the product’s quality.
Unsupported. Subcontracting manufacturing reduces control over product quality, but it doesn't necessarily mean lower quality. It also doesn’t mean that customers will question the quality of a product that has been manufactured by a subcontractor.
E
When a company manufactures some products in-house and subcontracts the manufacturing of others, the products made in-house will be of uniformly better quality.
Unsupported. Subcontracting manufacturing reduces control over product quality, but it doesn't necessarily mean lower quality. Just because a product is made in-house doesn’t ensure that it will be of better quality.
Sign up to star your favorites LSAT 140 - Section 3 - Question 09
January 19, 2014Sign up to star your favorites LSAT 140 - Section 3 - Question 01
January 19, 2014
Summarize Argument
The ad concludes that it costs more to bank at TekBank than at GreenBank. It supports this by noting that ATM transactions cost more at TekBank than at GreenBank.
Identify and Describe Flaw
This is the part to whole flaw, where the argument assumes that something true about one part of a whole must be true about the entire whole.
Here, the ad assumes that banking at TekBank costs more just because ATM use at TekBank costs more. However, other factors, like getting a loan or opening an account, might actually make TekBank cheaper than GreenBank.
A
bases a recommendation solely on economic factors without considering whether other factors are more important
The ad actually never makes a recommendation about which bank someone should use. It just concludes that one bank is more expensive than the other.
B
presents claims that are irrelevant to the issue under discussion in order to divert attention away from that issue
The cost of ATM use at each bank is relevant to the conclusion about which bank is more expensive. It’s just not sufficient evidence to conclude that TekBank is more expensive.
C
draws a conclusion about the overall cost of a service solely on the basis of a claim about the cost of one component of that service
The ad concludes that the overall cost of banking with TekBank is higher based solely on the claim that the cost of ATM use with TekBank is higher. But there might be other factors and fees that make GreenBank more expensive overall.
D
concludes that a component of a service must have a property that the service as a whole possesses
This is the opposite of the ad’s flaw. Instead of (D), the ad concludes that the service as a whole must have a property that one component of the service possesses.
E
concludes that a claim must be false because of the mere absence of evidence in its favor
This is the cookie-cutter flaw of assuming that a conclusion is false simply because its support is weak. The ad doesn’t make this mistake. In fact, it’s not concluding that any claim is false in the first place.
Sign up to star your favorites LSAT 140 - Section 3 - Question 08
January 19, 2014
Summarize Argument
The author concludes that the Korean sighting of the aurora borealis 5 days after John’s reported sighting of unusually large sunspots helps to confirm his reported observation. This is because sunspot activity is typically followed by the appearance of an aurora borealis after a time that average five days.
Notable Assumptions
The author assumes that the observed aurora borealis did not appear as a result of phenomena unconnected to sunspot activity. This overlooks the possibility that many other phenomena could give rise to an aurora borealis, which could account for the Korean sighting of the aurora borealis.
A
An aurora borealis can sometimes occur even when there has been no significant sunspot activity in the previous week.
If anything, this undermines the argument by suggesting the aurora borealis may have occurred without any sunspot activity occurring five days before it.
B
Chinese sources recorded the sighting of sunspots more than 1000 years before John of Worcester did.
This simply indicates that sunspots have occurred for many years. But it doesn’t help confirm John’s reported sighting of sunspots or connect the aurora borealis with confirmation of John’s sighting.
C
Only heavy sunspot activity could have resulted in an aurora borealis viewable at a latitude as low as that of Korea.
This strengthens by eliminating other potential causes of the aurora borealis. Only sunspot activity could have created an aurora borealis viewable in Korea, so there must have been sunspot activity before the Korean sighting.
D
Because it is impossible to view sunspots with the naked eye under typical daylight conditions, the sighting recorded by John of Worcester would have taken place under unusual weather conditions such as fog or thin clouds.
This has no clear impact on John’s sighting. This simply gives more details about when his sighting would have occurred.
E
John of Worcester’s account included a drawing of the sunspots, which could be the earliest illustration of sunspot activity.
The fact John drew sunspots doesn’t help connect the Korean sighting of aurora borealis with John’s sighting of sunspots. What do drawings have to do with the aurora borealis? Nothing.