For pollinating certain crops such as cranberries, bumblebees are far more efficient than honeybees. This is because a bumblebee tends to visit only a few plant species in a limited area, whereas a honeybee generally flies over a much broader area and visits a wider variety of species.

Summary

Bumblebees pollinate a smaller number of plant species in a more limited area than do honeybees. This makes bumblebees more efficient at pollinating some crops, including cranberries.

Strongly Supported Conclusions

Cranberries are more efficiently pollinated by pollinators who focus on a narrow range of species in a small area.

When a pollinator visits many species of plants, it decreases that pollinator’s efficiency in pollinating cranberries.

A
If a honeybee visits a wider variety of plant species than a bumblebee visits, the honeybee will be less efficient than the bumblebee at pollinating any one of those species.

Unsupported. This is too broad a claim. The stimulus doesn’t suggest that visiting a small number of plant species makes bumblebees more efficient at pollinating any species—it only makes them more efficient for “certain crops such as cranberries.”

B
The number of plant species other than cranberries that a bee visits affects the efficiency with which the bee pollinates cranberries.

Strongly supported. The difference in efficiency between the two kinds of bee is due to a difference in the geographic range and number of plant species visited by each kind of bee. This suggests that the number of additional plant species visited may affect efficiency.

C
The broader an area a bee flies over, the smaller the number of plant species that bee will be able to visit.

Anti-supported. Honeybees fly over a broader area than bumblebees do, and yet honeybees also visit a larger number of plant species.

D
Cranberries are typically found concentrated in limited areas that bumblebees are more likely than honeybees ever to visit.

Unsupported. The stimulus doesn’t suggest any reason why bumblebees would be more likely than honeybees to visit cranberries. If anything, honeybees visit a broader area and encounter more kinds of plants than bumblebees do.

E
The greater the likelihood of a given bee species visiting one or more plants in a given cranberry crop, the more efficient that bee species will be at pollinating that crop.

Unsupported. Bumblebees are more efficient at pollinating cranberries, but there’s nothing to suggest that this is because they’re somehow more likely to visit cranberries. If anything, honeybees visit a broader area and encounter more kinds of plants than bumblebees do.


32 comments

An independent computer service company tallied the service requests it receives for individual brands of personal computers. It found that, after factoring in each brand’s market share, KRV brand computers had the largest proportion of service requests, whereas ProBit brand computers had the smallest proportion of service requests. Obviously, ProBit is the more reliable personal computer brand.

Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that ProBit is more reliable computer brand than KRV. This is based on the fact that an independent service company found that, after factoring in each brand’s market share, KRV computers had the largest proportion of service requests, whereas ProBit computers had the smallest proportion of service requests.

Notable Assumptions
The author assumes that there’s no other explanation for the disparity in service requests other than ProBit’s greater reliability than KRV. This overlooks, for example, the possibility that the kind of person who buys KRV might be less tech-savvy and thus need more tech assistance or more likely to break their computers and seek repair.

A
The proportions of service requests for the other computer brands in the tally were clustered much closer to the ProBit level of service requests than to the KRV level.
We only care about the comparison between ProBit and KRV. Other brands’ service requests don’t impact this comparison.
B
For some computer brands, but not for others, most service requests are made to the manufacturer’s service department rather than to an independent service company.
This provides a potential alternate explanation for the disparity in service requests made to the independent service company. ProBit users might be more likely than KRV users to seek service at the manufacturer’s own service department.
C
The company that did the tally receives more service requests for ProBit brand computers than does any other independent computer service company.
If anything, this might strengthen the argument by showing that the independent service company isn’t just getting an unusually low number of ProBit service requests.
D
The computer brands covered in the computer service company’s tally differ greatly with respect to their market share.
The stimulus said that the tally of service requests was made after “factoring in each brand’s market share.” So differences in market share were already controlled for and don’t affect the statistic in the stimulus.
E
ProBit has been selling personal computers for many more years than has KRV.
If anything, this might provide a reason to think that ProBit is more reliable.

30 comments

Last year, pharmaceutical manufacturers significantly increased the amount of money they spent promoting new drugs, which they do mainly by sending sales representatives to visit physicians in their offices. However, two years ago there was an average of 640 such visits per representative, whereas last year that figure fell to 501. So the additional promotion must have been counterproductive, making physicians less willing to receive visits by pharmaceutical sales representatives.

Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that the additional promotion made physicians less willing to receive visits by sales representatives. This is based on the fact that after the additional promotion began, the average number of visits to physicians per representative fell from 640 to 501.

Notable Assumptions
The author assumes there’s no other explanation for the drop in average number of visits per representative.

A
Most pharmaceutical manufacturers increased the size of their sales forces so that their sales representatives could devote more time to each physician.
This presents another potential explanation for the drop in average number of visits per representative. If the number of representatives increased, so that representatives could spend more time on each physician, we’d expect average number of visits per rep to go down.
B
Physicians who receive visits from pharmaceutical sales representatives usually accept free samples of medication from the representatives’ companies.
Whether physicians accept free samples doesn’t affect how we interpret the drop in average number of visits per representative.
C
Most pharmaceutical companies did not increase the amount of money they spend promoting drugs through advertising targeted directly at consumers.
This concerns direct advertising to consumers, which has no clear impact on advertising in the form of sending representatives to physicians.
D
Most physicians who agree to receive a visit from a pharmaceutical sales representative will see that representative more than once during a given year.
This concerns the number of times a physician will see the same representative. This has no clear impact on how we interpret a statistic about how many overall visits an individual representative makes per year.
E
The more visits a physician receives from a pharmaceutical sales representative, the more likely he or she is to prescribe drugs made by that representative’s company.
This suggests that visits to a physician can be effective, if they occur. But the author’s position is that there were fewer visits this year. So, (E) is consistent with the author’s position.

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