Statistik: Béda antarrépisi

Often the concept is defined by saying that a statistic is an ''observable'' [[variabel acak]]. Statisticians often contemplate a parametrized family of [[probability distribution]]s, any member of which could be the distribution of some measurable aspect of each member of a [[populasi statistik]] from which a sample is drawn randomly. The value of the parameter is ''not observable'', since it depends on the whole population rather than on the sample. For example, the parameter may be the average height of 25-year-old men in North America. The height of the members of a sample of 100 such men are measured; the average of those 100 numbers is a statistic; the average of the heights of all members of the population is not a statistic (unless that has somehow also been ascertained). The ''difference'' between that observable sample average and the unobservable population average is an example of a random variable that is not a statistic; the reason it is ''random'' is that the sample was chosen randomly.