Critical Reasoning

A sudden increase in the production of elephant ivory artifacts on the Mediterranean coast of North Africa occurred in the tenth century. Historians explain this increase as the result of an area opening up as a new source of ivory and argue on this basis that the important medieval trade between North Africa and East Africa began at this period. B The many surviving letters of pre-tenth-century North African merchants include no mention of business transactions involving East Africa. C Excavations in East Africa reveal a tenth-century change in architectural style to reflect North African patterns. D Documents from Mediterranean Europe and North Africa that date back earlier than the tenth century show knowledge of East African animals. E East African carvings in a style characteristic of the tenth century depict seagoing vessels very different from those used by local sailors but of a type common in the Mediterranean.

It is true of both men and women that those who marry as young adults live longer than those who never marry. This does not show that marriage causes people to live longer, since, as compared with other people of the same age, young adults who are about to get married have fewer of the unhealthy habits that can cause a person to have a shorter life, most notably smoking and immoderate drinking of alcohol. Which of the following, if true, most strengthens the argument above?

Neither a rising standard of living nor balanced trade, by itself, establishes a country's ability to compete in the international marketplace. Both are required simultaneously since standards of living can rise because of growing trade deficits and trade can be balanced by means of a decline in a country's standard of living. If the facts stated in the passage above are true, a proper test of a country's ability to be competitive is its ability to

The difficulty with the proposed high-speed train line is that a used plane can be bought for one-third 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. Which of the following, if true, most severely weakens the argument presented above?

An overly centralized economy, not the changes in the climate, is responsible for the poor agricultural production in Country X since its new government came to power. Neighboring Country Y has experienced the same climate conditions, but while agricultural production has been falling in Country X, it has been rising in Country Y. Which of the following, if true, would most weaken the argument?

A recent report determined that although only three percent of drivers on Maryland highways equipped their vehicles with radar detectors, thirty-three percent of all vehicles ticketed for exceeding the speed limit were equipped with them. Clearly, drivers who equip their vehicles with radar detectors are more likely to exceed the speed limit regularly than are drivers who do not. B Drivers who are ticketed for exceeding the speed limit are more likely to exceed the speed limit regularly than are drivers who are not ticketed. C The number of vehicles that were ticketed for exceeding the speed limit was greater than the number of vehicles that were equipped with radar detectors. D Many of the vehicles that were ticketed for exceeding the speed limit were ticketed more than once in the time period covered by the report. E Drivers on Maryland highways exceeded the speed limit more often than did drivers on other state highways not covered in the report.

Although parapsychology is often considered a pseudoscience, it is in fact a genuine scientific enterprise, for it uses scientific methods such as controlled experiments and statistical tests of clearly stated hypotheses to examine the questions it raises. The conclusion above is properly drawn if which of the following is assumed?

Male bowerbirds construct elaborately decorated nests, or bowers. Basing their judgment on the fact that different local populations of bowerbirds of the same species build bowers that exhibit different building and decorative styles, researchers have concluded that the bowerbirds' building styles are a culturally acquired, rather than a genetically transmitted, trait. Which of the following, if true, would most strengthen the conclusion drawn by the researchers?

Outsourcing is the practice of obtaining from an independent supplier a product or service that a company has previously provided for itself. Since a company�s chief objective is to realize the highest possible year-end profits, any product or service that can be obtained from an independent supplier for less than it would cost the company to provide the product or service on its own should be outsourced. Which of the following, if true, most seriously weakens the argument?

To protect certain fledgling industries, the government of country Z banned imports of the types of products those industries were starting to make. As a direct result, the cost of those products to the buyers, several export-dependent industries in Z, went up, sharply limiting the ability of those industries to compete effectively in their export markets. Which of the following can be most properly inferred from the passage about the products whose importation was banned?

Last year the rate of inflation was 1.2 percent, but for the current year it has been 4 percent. We can conclude that inflation is on an upward trend and the rate will be still higher next year. Which of the following, if true, most seriously weakens the conclusion above?

According to a prediction of the not-so-distant future published in 1940, electricity would revolutionize agriculture. Electrodes would be inserted into the soil, and the current between them would kill bugs and weeds and make crop plants stronger. Which of the following, if true, most strongly indicates that the logic of the prediction above is flawed?

Insurance Company X is considering issuing a new policy to cover services required by elderly people who suffer from diseases that afflict the elderly. Premiums for the policy must be low enough to attract customers. Therefore, Company X is concerned that the income from the policies would not be sufficient to pay for the claims that would be made. Which of the following strategies would be most likely to minimize Company X's losses on the policies?

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 of the following, if true, most seriously weakens the conclusion above?

Although custom prosthetic bone replacements produced through a new computer-aided design process will cost more than twice as much as ordinary replacements, custom replacements should still be cost-effective. Not only will surgery and recovery time be reduced, but custom replacements should last longer; thereby reducing the need for further hospital stays. Which of the following must be studied in order to evaluate the argument presented above?

Even though most universities retain the royalties from faculty members inventions, the faculty members retain the royalties from books and articles they write. Therefore, faculty members should retain the royalties from the educational computer software they develop. The conclusion above would be more reasonably drawn if which of the following were inserted into the argument as an additional premise?

Excavation of the ancient city of Kourion on the island of Cyprus revealed a pattern of debris and collapsed buildings typical of towns devastated by earthquakes. Archaeologists have hypothesized that the destruction was due to a major earthquake known to have occurred near the island in A.D. 365. Which of the following, if true, most strongly supports the archaeologists' hypothesis?

Because no employee wants to be associated with bad news in the eyes of a superior, information about serious problems at lower levels is progressively softened and distorted as it goes up each step in the management hierarchy. The chief executive is therefore, less well informed about problems at lower levels than are his or her subordinates at those levels. The conclusion drawn above is based on the assumption that

The cost of producing radios in country Q is 10 percent less than the cost of producing radios in country Y. Even after transportation fees and tariff charges are added, it is still cheaper for a company to import radios from country Q to Country Y than to produce radios in Country Y. The statements above, if true, best support which of the following assertions?

When demand for a factory's products is high, more money is spent at the factory for safety precautions and machinery maintenance than when demand is low. Thus the average number of on-the-job accidents per employee each month should be lower during periods when demand is high than when demand is low and less money is available for safety precautions and machinery maintenance. Which of the following, if true about a factory when demand for its products is high, casts the most serious doubt on the conclusion drawn above?