Statistic

A statistic (singular) is a single measure of some attribute of a sample (e.g., its arithmetic mean value). It is calculated by applying a function (statistical algorithm) to the values of the items of the sample which are known together as a set of data.

More formally, statistical theory defines a statistic as a function of a sample where the function itself is independent of the sample's distribution; that is, the function can be stated before realization of the data. The term statistic is used both for the function and for the value of the function on a given sample.

A statistic is distinct from a statistical parameter, which is not computable because often the population is much too large to examine and measure all its items. However, a statistic, when used to estimate a population parameter, is called an estimator. For instance, the sample mean is a statistic which estimates the population mean, which is a parameter.

Read more about Statistic:  Examples

Other articles related to "statistic":

Logrank Test - Relationship To Other Statistics
... The logrank statistic can be derived as the score test for the Cox proportional hazards model comparing two groups ... is therefore asymptotically equivalent to the likelihood ratio test statistic based from that model ... The logrank statistic is asymptotically equivalent to the likelihood ratio test statistic for any family of distributions with proportional hazard alternative ...
Properties - Information of A Statistic
... Information of a statistic on model parameters can be defined in several ways ... information, which is defined on the statistic model induced by the statistic ...
Maximum Spacing Estimation - Goodness of Fit
... The statistic Sn(θ) is also a form of Moran or Moran-Darling statistic, M(θ), which can be used to test goodness of fit ... It has been shown that the statistic, when defined as is asymptotically normal, and that a chi-squared approximation exists for small samples ... In the case where we know the true parameter, Cheng Stephens (1989) show that the statistic has a normal distribution with where γ is the Euler–Mascheroni constant which is approximately 0.57722 ...
Control Limits
... at a distance of ±3 standard deviations of the plotted statistic from the statistic's mean ... which are completely independent of the distribution of the plotted sample statistic ...