Introduction to Statistics and Probability
What is Statistics?
Statistics is a mathematical science that deals with the collection, tabulation or presentation, analysis and interpretation of numerical or quantitative data. There are two fields of statistics: the descriptive statistics and the inferential statistics.
Descritive Statistics deals with methods of data presentation and the computations of summarizing values which describe group characteristics of data. Examples are measures of central tendency, variability, skewness, kurtosis, percentages or proportions, etc.
Inferential Statistics aims to give information about large groups of data or population without dealing with each and every element of these groups. It only uses a small but representative portion or sample of the total set of data in order to draw conclusions or judgments regarding the entire set of data. Examples are sampling, estimation, testing of hypotheses using z-test, t-test, chi-square test, F-test, etc.
Brief History of Statistics
The modern science of statistics traces its origins to two diverse interests of man: politics and entertainment or the games of chance.
Centuries before the time of Christ, the Egyptians, ancient Hebrews, the Babylonians, and the Romans collected and kept highly detailed records of resources and populations. The Old Testament bears testimony on how censuses of population and wealth were taken to provide the state with information not only for the purposes of taxes and trade, but also for the preparation of all available manpower and resources necessary to support the state’s aspirations for political and military power.
During the 16th century, governments of various western countries became interested in collecting information about their citizens and in conducting surveys that, by the 17th century, closely resemble our modern census. At about this time, insurance companies were beginning to thrive and were already compiling mortality tables to determine life insurance rates.
In the mid-18th century, statistics was described as “study of the political arrangements of the modern states of the known world.”
“Statistics” was derived from Italian word statista meaning statesman, one who is well-
versed with public affairs. Achenwall (1749) first used the word “statistics” defining it as “the political science of several countries.”
Games of chance, in the early 16th century, gave rise to the development of the principles of probability. Problems on how to increase their chances of winning were posed by gamblers who called upon mathematicians like Pascal, Fermat, Leibnitz, Cardano, Bernoulli, and others to provide optimum strategies for playing various games of chance. The answers given by mathematicians became the basis of modern statistical theory or the beginnings of the mathematics of probability.
During the 18th century, De Moivre’s discovery of the equation of the normal curve spurred the development of the theory of inductive or inferential statistics. The works of Laplace and Gauss proved useful in the application of statistics in astronomy.
During the 19th century, a Belgian astronomer, mathematician, statistician and sociologist, Adolph Quetelet applied statistical methods in the fields of education and sociology, and demonstrated that statistical techniques derived in one area of research are also applicable in other areas. Thus, Quetelet is known as the “Father of Modern Statistics”.
Contributions to the development of statistics were made by Sir Francis Galton in the fields of heredity and eugenics. In more recent times, Pearson, Fisher, and Gosset are notable names for their contributions to both theoretical and applied statistics.
American psychologist James McKeen Cattel who studied in Europe in the 1880s, contacted Galton and other European statisticians. Cattel and with other students (like Thorndike) began to apply statistical methods to psychological and educational problems when they returned to the United States. Their influence was such that in a few years theoretical and applied statistics courses were commonly taught in American universities.
In the Philippines, during the Spanish period, statistics started as estimates of population (thru:Legaspi, Riquel and Dasmarinas), account of socio-economic conditions of the people (thru:Loarca), cedulas, civil censuses, civil registration, surveys, etc. During the American regime, data collection became more systematized. The Bureau of Census and Statistics or BCS was created in 1940 to take care of all statistical activities of the Philippine government (Commonwealth Act No. 591).
In 1974, the BCS was reconstituted as a new agency to be known as the National Census and Statistics Office or NCSO (Presidential Decree No. 418). In 1987, the NCSO was renamed National Statistics Office or NSO (Executive Order No. 121). In the same EO, the National Statistical Coordination Board (NSCB) was created to be the policy-making and coordinating agency on statistical matters in the Philippines. Starting 1990, October of every year was declared as the National Statistics Month (Presidential Proclamation no. 647).
What are the scopes of Statistics?
The scope of statistics includes the collection, presentation, and summarization of data; the estimation of population parameters; and the testing of statitical hypotheses.
Thus, statistics is involved from the initial planning of the research, in the collection of data, in the analysis of the summarized results, to the evaluation of the uncertainty of any statistical inference drawn from the study.
What are the importance of Statistics?
Statistics has a general applicability. It is an essential tool in education, government, business, economics, medicine, psychology, sociology, sports, and others.
Statistics are gathered for the purpose of providing government heads with data necessary to guide them in policy-making, effective administration and in managing the affairs of the state (including fiscal and military matters).
In education, statistical tools are used to get information on enrolment, finance, physical facilities and so on for intelligent administration and management. It is used in the planning and conducting of experiments and researches in almost any field of work.
In business and economics, statistics play an important role in the exploration of new markets for a product, forecasting of business trends, control on the quality of goods produced, and improvement of personnel relations.
Everyday, life is influenced more and more by decisions based on quantitative information. The scientific sequence of experiments and the tests of hypotheses are now familiar approaches to problems in every area of activity.
According to Wells, “Statistical-thinking will one day be as necessary for efficient citizenship as the ability to read and write”. Moreover, a psychologist said that “statistics is the language of research just as music is the language of the soul.”
Despite the multi-uses of statistics, some caution should be considered. Statistics can also be misused. Impressive figures can be blown out of proportions of their real or imagined importance. Unscrupulous advertisers or people with vested interests make improper or unethical use of statistical methods. Questionable and even conflicting claims backed up with “statistics” can be accepted as true which leads one to believe that anything can be proven statistically. Moreover, faulty researches may be slanted to produce a particular outcome, that is, a statistical analysis is chosen to produce such outcome.
Read more about this on another website: Introduction to Statistics
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