短篇阅读
Few mathematical constructs seem as conceptually simple as that of randomness. According to the traditional definition, a number is random if it is chosen purely as the result of a probabilistic mechanism such as the roll of a fair die. Id their ground breaking work regarding complexity and the limitations of formal systems, mathematicians Gregory Chaitin and A.N. Kolmogorov force us to consider this last claim more closely.
Consider two possible outcomes of throwing a fair die three times: first, 1, 6, and 2; second 3, 3, and 3. Now let us construct two three-member sets based on the results. Though the first set— {1,6,2}—intuitively seems more random than the second—{3,3,3}, they are each as likely to occur, and thus according to the accepted definition, must be considered equally random. This unwelcome result prompts Chaitin and Kolmogorov to suggest the need for a new standard of randomness, one that relies on the internal coherence of the set as opposed to its origin.
1. Which of the following best describes the organization of the passage as whole?
A. A concept is introduced; a traditional definition is put forward; a thought experiment is described; a new definition is proposed; the traditional definition is amended as a result.
B. A concept is introduced; a traditional definition is supported by authorities; a thought experiment is described; the implications of the experiment are discussed.
C. A concept is introduced; a traditional definition is considered and rejected; a thought experiment is described; a new definition is proposed.
D. A concept is introduced; a traditional definition is called into question; a thought experiment is described; the implications of the experiment are discussed.
E. A concept is introduced; authorities are called in to reevaluate a definition; a thought experiment is described; the implications of the experiment are considered and rejected.
答案：C
解析：根据文章主旨，文章首先介绍了随机这个概念，对应选项C中：…concept…introduced…;然后再详细展开，并且说了这个定义的不足，对应选项C中：…traditional…considered and rejected;接着举例介绍了掷骰子实验，对应选项C中：…thought experiment…;最后说要有基于内在统一的新定义出现才可以：对应选项C中：…new definition…。
2. Consider each of the choices separately and select all that apply.
Which of the following is an inference made in the passage above?
A. The results of the same probabilistic mechanism will each be as likely as the other to occur.
B. According to the traditional definition of randomness, two numbers should be considered equally random if they result from the same probabilistic mechanism.
C. Different probabilistic mechanisms are likely to result in similar outcomes.
答案：B
解析：注意这不是一道单选题，而是一道针对每个选项是否正确的选择题。A选项不够严谨，若是按照传统定义则为正确，若是按照新定义则为错误，所以不能选;B选项符合传统定义，只要是从随机机器里抽选出来的都是随机的;C选项错在different…mechanisms，原文没有比较不同的随机机器。
以上就是小编为大家带来的12月15日机经啦，点击下方可下载GRE真题24套。