Summary
A person’s consumption of cholesterol and fat is one of the most important factors affecting a person’s serum cholesterol level. Serum cholesterol levels increase proportionally to increased consumption of fat and cholesterol until a threshold is reached. Once this threshold is reached, consumption of fat and cholesterol only cause a person’s serum cholesterol level to rise gradually even if consumption of fat and cholesterol increases dramatically. The threshold is one fourth the consumption level of these substances in the average North American diet.
Strongly Supported Conclusions
A person who consumes a fraction of the amount of cholesterol and fat compared to the average North American may not have a significantly different level of serum cholesterol.
A
The threshold can be lowered by lowering the dietary consumption of cholesterol and fat.
This answer is unsupported. We don’t know what factors could cause the threshold to be lowered, if at all.
B
People who consume an average North American diet cannot increase their consumption of cholesterol and fat without dramatically increasing their serum cholesterol levels.
This answer is anti-supported. We know that once a threshold is reached, dramatic increases in the consumption of cholesterol and fat can only result in a gradual increase of serum cholesterol.
C
People who consume half as much cholesterol and fat as in the average North American diet will not necessarily have half the average serum cholesterol level.
This answer is strongly supported. If a person is consuming half as much cholesterol and fat than the average North American, then that person is still consuming double the the amount of these substances compared to the threshold.
D
Serum cholesterol levels cannot be affected by nondietary modifications in behavior, such as exercising more or smoking less.
This answer is unsupported. We only know that consumption of cholesterol and fat is one of the most important factors affecting serum cholesterol. It is possible that there are other factors that could affect serum cholesterol levels.
E
People who consume less cholesterol and fat than the threshold cannot reduce their serum cholesterol levels.
This answer is anti-supported. We know from the stimulus that, before a threshold, serum cholesterol levels are directly proportional to a person’s consumption of fat and cholesterol.
Summarize Argument
The author concludes that beauty isn’t subjective. This is because earlier cultures’ beauty standards largely align with today’s.
Notable Assumptions
The author assumes that if today’s beauty standards align with those of early cultures, those beauty standards must be rooted in something objective rather than subjective. The author also assumes that we can know which works any given culture considered “most beautiful.” Finally, the author assumes that today’s beauty standards aren’t influenced by those of earlier cultures. If this were true, it would mean those standards are at least partially subjective.
A
Few contemporary artists have been significantly exposed to the art of earlier cultures.
We’re not concerned with contemporary artists. We need to know how people perceive beauty, and if that perception is rooted in something subjective or objective.
B
The arts held a much more important place in earlier cultures than they do in our culture.
It doesn’t matter how important the arts are to a given culture. We need to know about beauty.
C
Our own standard of beauty was strongly influenced by our exposure to works that were considered beautiful in earlier cultures.
If our standards of beauty today were influenced by older cultures, then those standards must be subjective. An objective, innate standard can’t be influenced by something else.
D
Much of what passes for important artistic work today would not be considered beautiful even by contemporary standards.
We need to know if our aesthetic reactions to earlier cultures’ art means that beauty is objective. This only talks about important artworks today.
E
In most cultures art is owned by a small social elite.
Ownership isn’t important. We’re concerned with how people judge and react to art.
Summarize Argument
The author concludes that rerouting the sewage is pointless. Why? Because most lobsters are too short-lived to suffer from the gill diseases that rerouting the sewage would prevent.
Notable Assumptions
The author assumes there is no other worthwhile reason for the sewage to be rerouted. In particular, he assumes that if lobsters are not harmed by sewage-caused gill diseases, then there’s no use in trying to prevent them.
A
Contaminants in the harbor other than sewage are equally harmful to lobsters.
This strengthens the argument. If non-sewage contaminants are equally dangerous, then rerouting the sewage will not protect the lobsters much, if at all.
B
Lobsters, like other crustaceans, live longer in the open ocean than in industrial harbors.
This does not say lobsters live only in the open ocean. It’s possible the lobsters caught for human consumption live mainly in industrial harbors.
C
Lobsters breed as readily in sewage-contaminated water as in unpolluted water.
This strengthens the argument by eliminating one possible reason for the sewage to be rerouted.
D
Gill diseases cannot be detected by examining the surface of the lobster.
This is not relevant. There’s no indication the detection of gill diseases from the outside makes lobsters more or less healthy or dangerous.
E
Humans often become ill as a result of eating lobsters with gill diseases.
This is a reason to reroute the sewage. Though lobsters themselves may not suffer from sewage-contaminated water, humans eating them will.
Summarize Argument: Phenomenon-Hypothesis
The researcher hypothesizes that adequate prenatal care significantly reduces the risk of low birth weight babies. This is supported by an observed correlation from hospital records: mothers who receive inadequate prenatal care are more likely to have low birth weight babies than mothers who receive adequate prenatal care. The records also noted that premature babies are more likely to have low birth weights.
Notable Assumptions
The researcher assumes that there is no alternative cause accounting for the observed correlation between inadequate prenatal care and low birth weight. For example, social or economic factors might instead cause both.
The researcher also assumes that the hospital records give a complete and accurate picture of the situation. If the hospitals’ data entry is flawed, then even the correlation may not be reliable.
The researcher also assumes that the hospital records give a complete and accurate picture of the situation. If the hospitals’ data entry is flawed, then even the correlation may not be reliable.
A
The hospital records indicate that many babies that are born with normal birth weights are born to mothers who had inadequate prenatal care.
Like (D), this does not weaken the researcher’s argument, because “many” normal birth weight babies being born despite inadequate prenatal care is totally consistent with an overall correlation between those factors. A statistic doesn’t require every individual case to match!
B
Mothers giving birth prematurely are routinely classified by hospitals as having received inadequate prenatal care when the record of that care is not available.
This weakens the researcher’s argument because it undermines the reliability of the hospital records. Premature babies usually have low birth weights, so this practice could easily skew the recorded correlation. And if the correlation isn’t solid, it’s hard to argue causation.
C
The hospital records indicate that low birth weight babies were routinely classified as having been born prematurely.
This does not weaken the researcher’s argument because, unlike (B), it does not affect the correlation between low birth weight and inadequate prenatal care. If the researcher’s hypothesis was about premature birth and low birth weight, this might weaken, but it’s not.
D
Some babies not born prematurely, whose mothers received adequate prenatal care, have low birth weights.
Like (A), this does not weaken the researcher’s argument, because the researcher is focusing on statistical trends, not individual cases. Even if “some” babies’ circumstances are different, that doesn’t mean the overall trend isn’t still reliable.
E
Women who receive adequate prenatal care are less likely to give birth prematurely than are women who do not receive adequate prenatal care.
This does not weaken the researcher’s argument because it’s completely consistent with adequate prenatal care preventing low birth weight. In fact, this suggests an indirect causation where premature birth acts as a mechanism for causing or preventing low birth weight.
Summarize Argument
The author claims that homeowners are generally unlikely to switch back to oil heating soon after having switched to natural gas due to its lower cost. Why? Because switching to gas in the first place required investing in new equipment, and presumably homeowners won’t want to duplicate that investment.
Notable Assumptions
The author assumes that the amount saved by continuing to use gas and not having to buy new oil-compatible equipment outweighs any savings from switching back to oil. In other words, equipment and oil have not gotten so much cheaper (and that gas hasn’t gotten so costly) that it would be worth switching again.
A
the price of natural gas to heat homes has remained constant, while the cost of equipment to heat homes with natural gas has fallen sharply
This does not weaken the argument, because it doesn’t challenge the author’s cost-benefit assumption. This gives us no reason to believe that oil heating now represents a cost savings over gas heating—we still don’t know which one is currently cheaper.
B
the price of home heating oil has remained constant, while the cost of equipment to heat homes with natural gas has risen sharply
This does not weaken the argument because it doesn’t indicate any kind of savings from switching back to oil. We’re only concerned with homeowners who currently use gas, so the cost of switching to gas is irrelevant. This also doesn’t tell us how oil and gas prices compare.
C
the cost of equipment to heat homes with natural gas has fallen sharply, while the price of home heating oil has fallen to 1970 levels
This does not weaken the argument. We’re not concerned with gas heating equipment prices, because we only care about current gas users. Like (E), the falling cost of oil is tempting, but we still don’t know how it compares with gas—maybe they both fell, and gas is still cheaper.
D
the cost of equipment to heat homes with oil has fallen sharply, while the price of heating with oil has fallen below the price of heating with natural gas
This weakens the argument because it indicates that oil is currently less expensive than gas, while also reducing the additional cost of getting new oil-heating equipment. This undermines the author’s cost-benefit assumption, thereby weakening.
E
the use of oil to heat homes has continued to decline, while the price of heating oil has fallen to 1970 levels
This does not weaken the argument, because like (C), just knowing that the cost of oil has fallen doesn’t actually tell us much: we still don’t know how oil and gas compare. The continued decline in oil heating also doesn’t do anything, because we don’t know why it’s happening.