陳蕙雅思教材 - 雅思閱讀精選 (Statistics)

Statistics

There were two widelydivergent influences on the early development of

statistical methods.Statistics had a mother who was dedicated to keeping

orderly records ofgovernmental units (state and statistics come from the

same Latin    root status) and a  gentlemanly gambling father who relied on

mathematics to increasehis skill at playing the odds    in gamesof chance.

The influence of the  mother on the offspring, statistics, isrepresented  

by counting,  measuring, describing, tabulating,  ordering, and  the  

taking  of censuses  --  all  of  which led  to  modern descriptive

statistics. From theinfluence of  the father came  modern inferential

statistics,  which is based squarely on           theoriesof probability.

Descriptive statisticsinvolves tabulating, depicting and describing

collections of data.These data may be     quantitative such asmeasures of

height, intelligence orgrade level -- variables that are characterized by

an       underlying continuum -- or the data may represent qualitativevariables,

such as sex, collegemajor or personality           type. Largemasses of data must

generally undergo aprocess of summarization or reduction before they are

comprehensible.Descriptive statistics is a tool for describing  or

summarizing or reducingto  comprehensible  form  theproperties of an

otherwise unwieldy massof data.

Inferential statistics isa formalized body of methods for solving another

class of problemsthat  present  great   difficulties  for  the unaided  

human  mind. This  general  class of  problems characteristically

involve  attempts to  make  predictions using  a  sample of  

observations.  For example, a school superintendent wishesto determine the

proportion of children ina large school system who come to school without

breakfast, have beenvaccinated for flu, or         whatever.Having a  little  

knowledge  of statistics,  the  superintendent  would know  that  it  is

unnecessary  and inefficient to question each child: theproportion for the

entire district could beestimated fairly

accurately      from a sample of as few as 100 children.Thus, the purpose of

inferential statistics isto predict or estimate       characteristicsof a

population from aknowledge of the characteristics of only a sample of the

population.

統計學

統計方法的早期發展受到兩種截然不同的影響。  統計學有一個"母親"，她致力於井井

有條地記錄政府機構的檔(國家和統計學這兩個詞源於同一個拉丁語詞根，status)，還有一

個有紳士般的賭博"父親"，他依靠數學來提高賭技，以便在幾率的遊戲中取勝。  "母親"對

其子女統計學的影響表現在計數、測量、描述、製錶、歸類和人口普查。  所有這些導致了 現代描述統計學的誕生。  

由於"父親"的影響則產生了完全基於概率論原理的現代推理統計 學。  描述統計學涉及對所收集資料的製表、製圖和描述。  這些資料可以是數量性的資料，

如高度、智商、或者是層級性的資料--具有連續性的變數--或資料也可以代表性質變量，如 性別、大學專業或性格類型等等。  

數量龐大的資料通常必須經過概括或刪減的程式才能為 人所理解。  描述統計學就是這樣一個工具，它對極其龐雜的資料進行描述、概括或刪減，

使其變成能為人理解的東西。  推理統計學是一套已定形了的方法體系，它解決的是光憑人 腦極難解決的另一類問題。  

這類問題的顯著特點是試圖通過取樣調查來作出預測。  例如， 有一位教育督察想知道在一個龐大的學校系統中，不吃早飯就上學的學生、已經做過防感冒

免疫的學生，或其它任何類型的學生占多大比例。  若具備一些統計學的知識，這位督察應 明白，詢問每個孩子是沒有必要而且沒有效率的，只要用 100

個孩子為樣本，他就可以相當 精確地得出這些孩子占整個學區的比例了。  因此，推理統計學的目的就是通過瞭解一個群

體中一些樣本的特性，從而對整個群體的特性進行推測和估算。