托福阅读模拟练习之统计.pdfVIP

智 课 网 托 福 备 考 资 料 托福阅读模拟练习之统计 早期的统计学发展有两个重要的分支，但是组成统计的各种方法还 是能够描述现代的统计的含义。那么现代统计的表现究竟有哪些呢?让 我们来看看这篇关于统计的文章。 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 unnecess