there were two widely pergent influence on the early development of tatitical method. tatitic had a mother who wa dedicated to keeping orderly record of government unit (tate and tatitic come from the ame latin root tatu) and a gentlemanly gambling father who relied on mathematic to increae hi kill at playing the odd in game of chance.
the influence of the mother on the offpring, tatitic, i repreented by counting, meauring, decribing, tabulating, ordering, and the taking of cenue-all of which led to modern decriptive tatitic. from the influence of the father came modern inferential tatitic, which i baed quarely on theorie of probability.
decribing collection involve tabulating, depicting and decribing collection of data. thee data may be quantitative uch a meaure of height, intelligence or grade level------variable that are characterized by an underlying continuum---or the data may repreent qualitative variable, uch a ex, college major or peronality type.
large mae of data mut generally undergo a proce of ummarization or reduction before they are comprehenible. decriptive tatitic i a tool for decribing or ummarizing or reducing to comprehenible form the propertie of an otherwie unwieldy ma of data.
inferential tatitic i a formalized body of method for olving another cla of problem that preent great of problem characteritically involve attempt to make prediction uing a ample of obervation. for example, a chool uperintendent wihe to determine the proportion of children in a large chool ytem who come to chool without breakfat, have been vaccinated for flu, or whatever.由好作网www.hAOzuowEn.com整理
having a little knowledge of tatitic, the uperintendent would know that it i unneceary and inefficient to quetion each child: the proportion for the ample of a few a 100 children. thu , the purpoe of inferential tatitic i to predict or etimate characteritic of a population from a knowledge of the characteritic of only a ample of the population.