LSAT Prep

Red blood cells in which the malarial-fever parasite resides are eliminated from a person’s body after 120 days. Because the parasite cannot travel to a new generation of red blood cells, any fever that develops in a person more than 120 days after that person has moved to a malaria-free region is not due to the malarial parasite. Which is the following, if true, most seriously weakens the conclusion above?

• The fever caused by the malarial parasite may resemble the fever caused by flu viruses.

• The anopheles mosquito, which is the principal insect carrier of the malarial parasite, has been eradicated in many parts of the world.

• Many malarial symptoms other than the fever, which can be suppressed with anti-malarial medication, can reappear within 120 days after the medication is discontinued.

• In some cases, the parasite that causes malarial fever travels to cells of the spleen, which are less frequently eliminated from a person’s body than are red blood cells.

• In any region infested with malaria-carrying mosquitoes, there are individuals who appear to be immune to malaria.

The number of people diagnosed as having a certain intestinal disease has dropped significantly in a rural county this year, as compared to last year. Health officials attribute this decrease entirely to improved sanitary conditions at water-treatment plants, which made for cleaner water this year and thus reduced the incidence of the disease. Which of the following, if true, would most seriously weaken the health officials’ explanation for the lower incidence of the disease?

• Many new water-treatment plants have been built in the last five years in the rural county.

• Bottled spring water has not been consumed in significantly different quantities by people diagnosed as having the intestinal disease, as compared to people who did not contract the disease.

• Because of a new diagnostic technique, many people who until this year would have been diagnosed as having the intestinal disease are now correctly diagnosed as suffering from intestinal ulcers.

• Because of medical advances this year, far fewer people who contract the intestinal disease will develop severe cases of the disease.

• The water in the rural county was brought up to the sanitary standards of the water in neighboring counties ten years ago.

With the emergence of biotechnology companies, it was feared that they would impose silence about proprietary results on their in-house researchers and their academic consultants. This constraint, in turn, would slow the development of biological science and engineering. Which of the following, if true, would tend to weaken most seriously the prediction of scientific secrecy described above?

• Biotechnological research funded by industry has reached some conclusions that are of major scientific importance.

• When the results of scientific research are kept secret, independent researchers are unable to build on those results.

• Since the research priorities of biotechnology companies are not the same as those of academic institutions, the financial support of research by such companies distorts the research agenda.

• To enhance the companies’ standing in the scientific community, the biotechnology companies encourage employees to publish their results, especially results that are important.

• Biotechnology companies devote some of their research resources to problems that are of fundamental scientific importance and that are not expected to produce immediate practical applications.

A group of children of various ages was read stories in which people caused harm, some of those people doing so intentionally, and some accidentally. When asked about appropriate punishments for those who had caused harm, the younger children, unlike the older ones, assigned punishments that did not vary according to whether the harm was done intentionally or accidentally. Younger children, then, do not regard people’s intentions as relevant to punishment. Which of the following, if true, would most seriously weaken the conclusion above?

• In interpreting these stories, the listeners had to draw on a relatively mature sense of human psychology in order to tell whether harm was produced intentionally or accidentally.

• In these stories, the severity of the harm produced was clearly stated.

• Younger children are as likely to produce harm unintentionally as are older children.

• The older children assigned punishment in a way that closely resembled the way adults had assigned punishment in a similar experiment.

• The younger children assigned punishments that varied according to the severity of the harm done by the agents in the stories.

Dental researchers recently discovered that toothbrushes can become contaminated with bacteria that cause pneumonia and strep throat. They found that contamination usually occurs after toothbrushes have been used for four weeks. For that reason, people should replace their toothbrushes at least once a month. Which of the following, if true, would most weaken the conclusion above?

• The dental researchers could not discover why toothbrush contamination usually occurred only after toothbrushes had been used for four weeks.

• The dental researchers failed to investigate contamination of toothbrushes by viruses, yeasts, and other pathogenic microorganisms.

• The dental researchers found that among people who used toothbrushes contaminated with bacteria that cause pneumonia and strep throat, the incidence of these diseases was no higher than among people who used uncontaminated toothbrushes.

• The dental researchers found that people who rinsed their toothbrushes thoroughly in hot water after each use were as likely to have contaminated toothbrushes as were people who only rinsed their toothbrushes hurriedly in cold water after each use.

• The dental researchers found that, after six weeks of use, greater length of use of a toothbrush did not correlate with a higher number of bacteria being present.

Shelby Industries manufactures and sells the same gauges as Jones Industries. Employee wages account for forty percent of the cost of manufacturing gauges at both Shelby Industries and Jones Industries. Shelby Industries is seeking a competitive advantage over Jones Industries. Therefore, to promote this end, Shelby Industries should lower employee wages. Which of the following, if true, would most weaken the argument above?

• Because they make a small number of precision instruments, gauge manufacturers cannot receive volume discounts on raw materials.

• Lowering wages would reduce the quality of employee work, and this reduced quality would lead to lowered sales.

• Jones Industries has taken away twenty percent of Shelby Industries’ business over the last year.

• Shelby Industries pays its employees, on average, ten percent more than does Jones Industries.

• Many people who work for manufacturing plants live in areas in which the manufacturing plant they work for is the only industry.

Although migraine headaches are believed to be caused by food allergies, putting patients on diets that eliminate those foods to which the patients have been demonstrated to have allergic migraine reactions frequently does not stop headaches. Obviously, some other cause of migraine headaches besides food allergies much exist.

• Many common foods elicit an allergic response only after several days, making it very difficult to observe links between specific foods patients eat and headaches they develop.

• Food allergies affect many people who never develop the symptom of migraine headaches.

• Many patients report that the foods that cause them migraine headaches are among the foods that they most enjoy eating.

• Very few patients have allergic migraine reactions as children live migraine-free adult lives once they have eliminated from their diets foods to which they have been demonstrated to be allergic.

• Very rarely do food allergies cause patients to suffer a symptom more severe than that of migraine headaches.

The difficulty with the proposed high-speed train line is that a used plane can be bought for onethird the price of the train line, and the plane, which is just as fast, can fly anywhere. The train would be a fixed linear system, and we live in a world that is spreading out in all directions and in which consumers choose the free-wheel systems (cars, buses, aircraft), which do not have fixed routes. Thus a sufficient market for the train will not exist.

• Cars, buses, and planes require the efforts of drivers and pilots to guide them, whereas the train will be guided mechanically.

• Cars and buses are not nearly as fast as the high-speed train will be.

• Planes are not a free-wheel system because they can fly only between airports, which are less convenient for consumers than the high-speed train’s stations would be.

• The high-speed train line cannot use currently underutilized train stations in large cities.

• For long trips, most people prefer to fly rather than to take ground-level transportation.

Which of the following, if true, most seriously weakens the argument above?

• Last year’s best-selling airline seat was not the safest airline seat on the market.

• No airline company has announced that it would be making safe seating a higher priority this year.

• The price of fuel was higher this year than it had been in most of the years when the safest airline seats sold poorly.

• Because of increases in the cost of materials, all airline seats were more expensive to manufacture this year than in any previous year.

• Because of technological innovations, the safest airline seat on the market this year weighed less than most other airline seats on the market.

If, on the basis of the evidence above, it is argued that PRP contracts increase worker productivity, which of the following, if true, would most seriously weaken that argument?

• Results similar to those cited for the metal-working industry have been found in other industries where PRP contracts are used.

• Under PRP contracts costs other than labor costs, such as plant, machinery, and energy, make up an increased proportion of the total cost of each unit of output.

• Because introducing PRP contracts greatly changes individual workers’ relationships to the firm, negotiating the introduction of PRP contracts in complex and time consuming.

• Many firms in the metalworking industry have modernized production equipment in the last five years, and most of these introduced PRP contracts at the same time.

• In firms in the metalworking industry where PRP contracts are in place, the average take-home pay is 15 percent higher than it is in those firms where workers have more traditional contracts.