A population parameter, or simply a parameter, is a numerical measure, such as the mean, median, mode, range, variance, or standard deviation, that is computed for a population data collection. A sample statistic, or simply a statistic, is a summary measure that is computed for a sample data set. We make use of numerical measurements that can be computed for a population (parameters) or a sample (statistics). Numerical descriptive measures, also known as descriptive statistics, are summary statistics that quantitatively describe the main features of a dataset. There are four measures – measures of central tendency, measures of dispersion, measures of shape, measures of association.
Various syntaxes can be used to get the summary statistics. Some of the syntaxes below give additional comprehensive info about the data/variable.
> summary(mtcars$mpg)
> summary(mtcars)
> fivenum(mtcars$mpg)
> library(pastecs)
> stat.desc(mtcars$mpg)
> example(stat.desc)
> library(psych)
> describe(mtcars$mpg)
> library(DescTools)
> Desc(mtcars$mpg)