Critical Reasoning

Since the mayor�s publicity campaign for Greenville�s bus service began six months ago, morning automobile traffic into the midtown area of the city has decreased seven percent. During the same period, there has been an equivalent rise in the number of persons riding buses into the midtown area. Obviously, the mayor�s publicity campaign has convinced many people to leave their cars at home and ride the bus to work.. Which of the following, if true, casts the most serious doubt on the conclusion drawn above?

Bank depositors in the United States are all financially protected against bank failure because the government insures all individuals' bank deposits. An economist argues that this insurance is partly responsible for the high rate of bank failures, since it removes from depositors any financial incentive to find out whether the bank that holds their money is secure against failure. If depositors were more selective, then banks would need to be secure in order to compete for depositors' money. Which of the following, if true, most seriously weakens the economist's argument?

Automobile Dealer's Advertisement: The Highway Traffic Safety Institute reports that the PZ 1000 has the fewest injuries per accident of any car in its class. This shows that the PZ 1000 is one of the safest cars available today. Which of the following, if true, most seriously weakens the argument in the advertisement?

In the arid land along the Colorado River, use of the river's water is strictly controlled: farms along the river each have a limited allocation that they are allowed to use for irrigation. But the trees that grow in narrow strips along the river�s banks also use its water. Clearly, therefore, if farmers were to remove those trees, more water would be available for crop irrigation Which of the following, if true, most seriously weakens the argument?

In 1987 sinusitis was the most common chronic medical condition in the United States, followed by arthritis and high blood pressure, in that order. The incidence rates for both arthritis and high blood pressure increase with age, but the incidence rate for sinusitis is the same for people of all ages. The average age of the United States population will increase between 1987 and 2000. Which of the following conclusions can be most properly drawn about chronic medical conditions in the United States from the information given above?

When people evade income taxes by not declaring taxable income, a vicious cycle results. Tax evasion forces lawmakers to raise income tax rates, which causes the tax burden on nonevading taxpayers to become heavier. This, in turn, encourages even more taxpayers to evade income taxes by hiding taxable income. The vicious cycle described above could not result unless which of the following were true?

The proportion of women among students enrolled in higher education programs has increased over the past decades. This is partly shown by the fact that in 1959, only 11 percent of the women between twenty and twenty-one were enrolled in college, while in 1981, 30 percent of the women between twenty and twenty-one were enrolled in college. To evaluate the argument above, it would be most useful to compare 1959 and 1981 with regard to which of the following characteristics?

Mouth cancer is a danger for people who rarely brush their teeth. In order to achieve early detection of mouth cancer in these individuals, a town's public health officials sent pamphlet to all town residents, describing how to perform weekly self-examinations of the mouth for lumps. Which of the following, if true, is the best criticism of the pamphlet as a method of achieving the public health official's goal?

Crops can be traded on the futures market before they are harvested. If a poor corn harvest is predicted, prices of corn futures rise; if a bountiful corn harvest is predicted, prices of corn futures fall. This morning meteorologists are predicting much-needed rain for the corn-growing region starting tomorrow. Therefore, since adequate moisture is essential for the current crop�s survival, prices of corn futures will fall sharply today. Which of the following, if true, most weakens the argument above?

If the airspace around centrally located airports were restricted to commercial airliners and only those private planes equipped with radar, most of the private-plane traffic would be forced to use outlying airfields. Such a reduction in the amount of private-plane traffic would reduce the risk of midair collision around the centrally located airports The conclusion drawn in the first sentence depends on which of the following assumptions?

The price the government pays for standard weapons purchased from military contractors is determined by a pricing method called �historical costing.� Historical costing allows contractors to protect their profits by adding a percentage increase, based on the current rate of inflation, to the previous year�s contractual price. Which of the following statements, if true, is the best basis for a criticism of historical costing as an economically sound pricing method for military contracts?

Outsourcing is the practice of obtaining from an independent supplier a product or service that a company has previously provided for itself. Vernon, Inc, a small manufacturing company that has in recent years experienced a decline in its profits, plans to boost its profits by outsourcing those parts of its business that independent suppliers can provide at a lower cost than Vernon can itself. Which of the following, if true, most strongly supports the prediction that Vernon's plan will achieve its goal?

The interview is an essential part of a successful hiring program because, with it, job applicants who have personalities that are unsuited to the requirements of the job will be eliminated from consideration. The argument above logically depends on which of the following assumptions?

Transnational cooperation among corporations is experiencing a model renaissance among United States firms, even though projects undertaken by two or more corporations under a collaborative agreement are less profitable than projects undertaken by a single corporation. The advantage of transnational cooperation is that such joint international projects may allow United States firms to win foreign contracts that they would not otherwise be able to win. Which of the following statements by a United States corporate officer best fits the situation of United States firms as described in the passage above?

Dental researchers recently discovered that tooth-brushes can become contaminated with bacterial 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 imposition of quotas limiting imported steel will not help the big American steel mills. In fact, the quotas will help �mini-mills� flourish in the United States. Those small domestic mills will take more business from the big American steel mills than would have been taken by the foreign steel mills in the absence of quotas. Which of the following, if true, would cast the most serious doubt on the claim made in the last sentence above?

On the basis of a decrease in the college-age population, many colleges now anticipate increasingly smaller freshman classes each year. Surprised by a 40 percent increase in qualified applicants over the previous year, however, administrators at Nice College now plan to hire more faculty for courses taken by all freshmen. Which of the following statements about Nice College�s current qualified applicants, if true, would strongly suggest that the administrators� plan is flawed?

Since the routine use of antibiotics can give rise to resistant bacteria capable of surviving antibiotic environments, the presence of resistant bacteria in people could be due to the human use of prescription antibiotics. Some scientists, however, believe that most resistant bacteria in people derive from human consumption of bacterially infected meat. Which of the following statements, if true, would most significantly strengthen the hypothesis of the scientists?

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?

Parasitic wasps lay their eggs directly into the eggs of various host insects in exactly the right numbers for any suitable size of host egg. If they laid too many eggs in a host egg, the developing wasp larvae would compete with each other to the death for nutrients and space. If too few eggs were laid, portions of the host egg would decay, killing the wasp larvae. Which of the following conclusions can properly be drawn from the information above?