A
There exist several different techniques for collecting samples of prehistoric pigments on limestone.
B
Laboratory procedures exist that can remove all the limestone from a sample of prehistoric paint on limestone.
C
The age of the limestone itself can be determined from samples that contain no vegetable-based paint.
D
Prehistoric artists did not use anything other than vegetable matter to make their paints.
E
The proportion of carbon to other elements in limestone is the same in all samples of limestone.
A
The actions of humans and animals are believed to be motivated by similar instincts, but these instincts are easier to discern in animals.
B
The law forbids certain experiments on humans but permits them on animals.
C
It is generally less expensive to perform experiments on animals than it is to perform them on humans.
D
Proper understanding of human personality is thought to provide a model for better understanding the personality of animals.
E
Field observations of the behavior of young animals often inspire insightful hypotheses about human personality development.
A group of 1,000 students was randomly selected from three high schools in a medium-sized city and asked the question, “Do you plan to finish your high school education?” More than 89 percent answered “Yes.” This shows that the overwhelming majority of students want to finish high school, and that if the national dropout rate among high school students is high, it cannot be due to a lack of desire on the part of the students.
Summarize Argument
The author concludes that most students want to finish high school and that if there’s a high high school dropout rate, it’s not due to students’ lack of desire. He supports this with a survey of 1,000 randomly selected students from three high schools in a medium-sized town, where over 89% said they planned to finish high school.
Identify and Describe Flaw
This is a cookie-cutter example of a flawed survey. The author draws a conclusion about all high school students based on an unrepresentative survey. Even though the students surveyed were randomly selected, they were still only chosen from three high schools in one medium-sized town. The author mistakenly assumes that 1,000 students from this town represent all high school students.
A
fails to justify its presumption that 89 percent is an overwhelming majority
The author doesn’t need to justify this presumption because 89 percent is an overwhelming majority. He isn’t making an unreasonable assumption here.
B
attempts to draw two conflicting conclusions from the results of one survey
The author does draw two conclusions— that most students want to finish high school and that a high high school dropout rate wouldn’t be due to students’ lack of desire— from one survey. But these conclusions don’t conflict with one another.
C
overlooks the possibility that there may in fact not be a high dropout rate among high school students
The author doesn’t overlook this possibility. In fact, he explicitly addresses it by saying, “If the national dropout rate...is high...”
D
contradicts itself by admitting that there may be a high dropout rate among students while claiming that most students want to finish high school
The author does claim that most students want to finish high school and he admits the possibility of a high dropout rate. But these statements don’t contradict each other. There could be many students who drop out of school despite wanting to finish.
E
treats high school students from a particular medium-sized city as if they are representative of high school students nationwide
This explains the author’s key flaw. He draws a conclusion about all high school students based on a survey of 1,000 students from a single city.