托福阅读模拟练习（3）

serein

　　There were two widely divergent influences on the early development of statistical methods. Statistics had a mother who was dedicated to keeping orderly records of governmental units (state and statistics come from the same Latin root, status) and a gentlemanly gambling father who relied on mathematics to increase his skill at playing the odds in games of chance. The influence of the mother on the offspring, statistics, is represented by counting, measuring, describing, tabulating, ordering. and the taking of censuses —— all of which led to modern descriptive statistics. From the influence of the father came modern inferential statistics, which is based squarely on theories of probability.
　　Descriptive statistics involves tabulating, depicting, and describing collections of data. These data may be quantitative, such as measures of height, intelligence, or grade level - variables that are characterized by an underlying continuum - orthe data may represent qualitative variables, such as sex, college major, or personality type. Large masses of data must generally undergo a process of summarization or reduction before they are comprehensible. Descriptive statistics is a tool for describing or summarizing or reducing to comprehensible form the properties of an otherwise unwieldy mass or data. Inferential statistics is a formalized body of methods for solving another class of　problems that present great difficulties for the unaided human mind. This general class of problems characteristically involves attempts to make predictions using a sample of observations. For example, a school superintendent wishes to determine the proportion of children in a large school system who come to school without breakfast, have been vaccinated for flu, or whatever. Having a little knowledge of statistics, the superintendent would know that it is unnecessary and inefficient to question each child; the proportion for the entire district could be estimated fairly accurately from a sample of as few as l00 children. Thus, the purpose of inferential statistics is to predict or estimate characteristics of a population from a knowledge of the characteristics of only a sample of the population.
　　21. With what is the passage mainly concerned ?
　　(A) The drawbacks of descriptive and inferential statistics
　　(B) Applications of inferential statistics
　　(C) The development and use of statistics
　　(D) How to use descriptive statistics
　　22. The word "divergent" in line 1 is closest in meaning to
　　(A) different
　　(B) distributed
　　(C) recorded
　　(D) prominent
　　23. According to the first paragraph, counting and census-taking arc associated with
　　(A) inferential statistics
　　(B) descriptive statistics
　　(C) unknown variables
　　(D) qualitative changes
　　24. Why does the author mention the "mother" and "father" in the first paragraph?
　　-
　　(A) To point out that parents can teach their children statistics
　　(B) To introduce inferential statistic
　　(C) To explain that there are different kinds of variables
　　(D) To present the background of statistics in a humorous and understandable way
　　25. The word "squarely" in line 8 could best be replaced by
　　(A) solidly
　　(B) geometrically
　　(C) rectangularly
　　(D) haphazrardly
　　26. Which of the following is NOT given an example of a qualitative variable?
　　(A) Gender
　　(B) Height
　　(C) College major
　　(D) Type of personality
　　27. The word "they" in line 13 refers to
　　(A) variables
　　(B) masses
　　(C) descriptive statistics
　　(D) properties
　　28. Which of the following statements about descriptive statistics is best supported by thepassage?
　　(A) It reduces large amounts of data to a more comprehensible form.
　　(B) It is based on probability.
　　(C) It can be used by people with little knowledge of mathematics.
　　(D) It measures only qualitative differences.
　　29. The word "unwieldy" in line 15 is closest in meaning to
　　(A) unmanageable
　　(B) unpredictable
　　(C) understandable
　　(D) unreliable
　　30. According to the passage, what is the purpose of examining a sample of a population?
　　(A) To compare different groups
　　(B) To predict characteristics of the entire population
　　(C) To detect differences not observable in the whole population
　　(D) To compile more accurate data