Six years ago, the police force of Harrisville was reduced, in an effort to make a smaller but more efficient force. In the first two years, crimes in Harrisville, especially by career criminals, were at a higher rate than they had been in the previous decades. Then, for the most recent four years, the crime rate has been the lowest in the seventy years on record, with the significant drop in crimes by career criminals. Which of the following, if true, most helps to explain the change in the crime rate between the first two years after the change and the last four years?

The Ixazyiquo tribe are believed to be one of the few remaining tribes in the country of Malugiato to have never had any contact with the Lamandians, settlers who arrived in Malugiain during the last hundred years. Using satellite imagery, a team of anthropologists determined that the Ixazyiquo land is covered with thriving banana plantations. The anthropologists conclude that the Ixazyiquo tribe has in fact had direct contact with the Lamandians.Which of the following, if true, would best support the anthropologists` conclusion?

A mechanized factory with over 3000 separate conveyor belts wants to minimize the cost associated with maintenance, repair, and replacement of these belts. The conveyer belts currently are composed vulcanized rubber around a cotton web base, but the factory owners are investigating new plastic polymer design. For any given size belt, the costs for belts of the two compositions are comparable. Compared to the current rubber/cotton belts, the plastic polymer belts are lighter and easier to move, so operating the conveyor belts made of plastic polymer would consume less electric energy. A change from rubber/cotton belts to plastic polymer belts would require minor modification to some of the drive cylinders of the conveyor belts, but the costs of these changes are negligible. Which of the following would it be most useful to know in determining whether switching to the plastic polymer conveyor belts would be likely to help minimize the factory's cost related to its conveyor belt system?

Last year, the composite El-Hi education (CEHE) ranking for Silver County was its lowest score on record, since composite were first calculated in 1964. The CEHE ranking is a sophisticated weighed average of standardized testing results from Grade 1 to Grade 12. This year, the testing result for grades 1-6 in Silver County are about the same as they were last year, and the testing results for high school (grades 9-12) in Silver County are lower than last year's high school results in Silver County. Surely the middle school testing results (grades 7-9) in Silver County will also be as low as, or lower than, last year's results. Therefore, Silver County will undoubtedly establish a new low in its CEHE ranking. In the argument, the two portions in boldface play which of the following roles?

Mayor of Smalltown: Instituting high taxes on sodas, which are currently untaxed in Smalltown, has been shown in the past year to encourage people to reduce their intake of soda and live healthier lifestyles. Because the effects of such taxes on local businesses have not yet been determined, though, I believe we should wait before implementing such a tax.Activist: Your position is inconsistent with previous actions you have taken. You have implemented many laws that have decreased local businesses' revenues in order to help consumers, so concern for local businesses cannot be the true reason you refuse to pass this law now.The activist's argument is flawed because it fails to consider that

An analysis of the XO Candy Corporation divided its products into two categories: chocolate-based candies and non-chocolate-based candies. The analysis shows that, unlike the non-chocolate candies, few chocolate candies sold enough units to be profitable. Nevertheless, stopping production of the unprofitable chocolate candies will not necessarily make the entire company more profitable, because__________________ . Which of the following most logically completes the passage?

Homeowner Representative: Statistics show that burglars often target houses that appear unoccupied. Therefore, when homeowners are away from their homes for several days, we recommend that they leave lights on, to give the impression that the house is occupied. Crime Expert: The same lights continuously on all night long with no change give a potential burglar a clear signal that the house is unoccupied. The Crime Expert uses which of the following techniques in responding to the Homeowner Representative?

Because ethylene dibromide, a chemical used to fumigate grain, was blamed for the high rate of nerve damage suffered by people who work in grain-processing plants, many such plants switched to other chemical fumigants two years ago. Since then, however, the percentage of workers at these plants who were newly diagnosed with nerve damage has not dropped significantly. Therefore, either ethylene dibromide was wrongly blamed or else the new chemicals also cause nerve damage.

Which of the following is an assumption on which the argument depends?

Lightbox, Inc., owns almost all of the movie theaters in Washington County and has announced plans to double the number of movie screens it has in the county within five years. Yet attendance at Lightbox's theaters is only just large enough for profitability now and the county's population is not expected to increase over the next ten years. Clearly, therefore, if there is indeed no increase in population, Lightbox's new screens are unlikely to prove profitable.

Which of the following, if true about Washington County, most seriously weakens the argument?

In the past the country of Siduria has relied heavily on imported oil. Siduria recently implemented a program to convert heating systems from oil to natural gas. Siduria already produces more natural gas each year than it burns, and oil production in Sidurian oil fields is increasing at a steady pace. If these trends in fuel production and usage continue, therefore, Sidurian reliance on foreign sources for fuel should decline soon.

Which of the following is an assumption on which the argument depends?

Many large department stores in Montalia now provide shopping carts for their customers. Since customers using shopping carts tend to buy more than those without shopping carts, most of these stores are experiencing strong sales growth, while most other department stores are not. Therefore, in order to boost sales, managers of Jerrod's, Montalia's premier department store, are planning to purchase shopping carts and make them available to the store's customers next month.

Which of the following, if true, casts most doubt whether the managers' plan, if implemented, will achieve its goal?

A mosquito bite can transmit to a person the parasite that causes malaria, and the use of mosquito nets over children's beds can significantly reduce the incidence of malarial infection for children in areas where malaria is common. Yet public health officials are reluctant to recommend the use of mosquito nets over children's beds in such areas.

Which of the following, if true, would provide the strongest grounds for the public health officials' reluctance?

For similar cars and drivers, automobile insurance for collision damage has always cost more in Greatport than in Fairmont. Police studies, however, show that cars owned by Greatport residents are, on average, slightly less likely to be involved in a collision than cars in Fairmont. Clearly, therefore, insurance companies are making a greater profit on collision-damage insurance in Greatport than in Fairmont.

Which of the following is an assumption on which the argument depends?

Criminologist: Some legislators advocate mandating a sentence of life in prison for anyone who, having twice served sentences for serious crimes, is subsequently convicted of a third serious crime. These legislators argue that such a policy would reduce crime dramatically, since it would take people with a proven tendency to commit crimes off the streets permanently. What this reasoning overlooks, however, is that people old enough to have served two prison sentences for serious crimes rarely commit more than one subsequent crime. Filling our prisons with such individuals would have exactly the opposite of the desired effect, since it would limit our ability to incarcerate younger criminals, who commit a far greater proportion of serious crimes.

In the argument as a whole, the two boldfaced portions play which of the following roles?

Eurasian watermilfoil, a weed not native to Frida Lake, has reproduced prolifically since being accidentally introduced there. In order to eliminate the weed, biologists proposed treating infested parts of the lake with a certain herbicide that is nontoxic for humans and aquatic animals. However, the herbicide might damage populations of certain rare plant species that the lake contains. For this reason local officials rejected the proposal.

Which of the following, if true, points out the most serious weakness in the officials' grounds for rejecting the biologists' proposal?