Editing Descriptive statistics (section)

{{short description|Type of statistics}}
{{Research}}

A '''descriptive statistic''' (in the [[count noun]] sense) is a [[summary statistic]] that quantitatively describes or summarizes features from a collection of [[information]],<ref>{{cite book |last=Mann |first=Prem S. |year=1995 |title=Introductory Statistics |edition=2nd |publisher=Wiley |isbn=0-471-31009-3 }}</ref> while '''descriptive statistics''' (in the [[mass noun]] sense) is the process of using and analysing those statistics. Descriptive statistics is distinguished from [[statistical inference|inferential statistics]] (or inductive statistics) by its aim to summarize a [[Sample (statistics)|sample]], rather than use the data to learn about the [[statistical population|population]] that the sample of data is thought to represent.<ref>{{Citation|author-first1=Andrew N.|author-last1=Christopher|title=Drawing Conclusions From Data: Descriptive Statistics, Inferential Statistics, and Hypothesis Testing|date=2017|url=http://dx.doi.org/10.4135/9781506304144.n6|work=Interpreting and Using Statistics in Psychological Research|pages=145–183|location=Thousand Oaks, CA|publisher=SAGE Publications, Inc|doi=10.4135/9781506304144.n6|isbn=978-1-5063-0416-8|access-date=2021-06-01}}</ref> This generally means that descriptive statistics, unlike inferential statistics, is not developed on the basis of [[probability theory]], and are frequently [[nonparametric statistics]].<ref>{{cite book |last=Dodge |first=Y. |year=2003 |title=The Oxford Dictionary of Statistical Terms |publisher=OUP |isbn=0-19-850994-4 |url-access=registration |url=https://archive.org/details/oxforddictionary0000unse }}</ref> Even when a data analysis draws its main conclusions using inferential statistics, descriptive statistics are generally also presented.<ref>{{Citation|author-first1=Andrew N.|author-last1=Christopher|title=Drawing Conclusions From Data: Descriptive Statistics, Inferential Statistics, and Hypothesis Testing|date=2017|url=http://dx.doi.org/10.4135/9781506304144.n6|work=Interpreting and Using Statistics in Psychological Research|pages=145–183|location=Thousand Oaks, CA|publisher=SAGE Publications, Inc|doi=10.4135/9781506304144.n6|isbn=978-1-5063-0416-8|access-date=2021-06-01}}</ref> For example, in papers reporting on human subjects, typically a table is included giving the overall [[sample size]], sample sizes in important subgroups (e.g., for each treatment or exposure group), and [[demographic]] or clinical characteristics such as the [[average]] age, the proportion of subjects of each sex, the proportion of subjects with related [[comorbidity|co-morbidities]], etc.

Some measures that are commonly used to describe a data set are measures of [[central tendency]] and measures of variability or [[Statistical dispersion|dispersion]]. Measures of central tendency include the [[mean]], [[median]] and [[Mode (statistics)|mode]], while measures of variability include the [[standard deviation]] (or [[variance]]), the minimum and maximum values of the variables, [[kurtosis]] and [[skewness]].<ref name=Inv>Investopedia, [http://www.investopedia.com/terms/d/descriptive_statistics.asp#axzz2DxCoTnMM Descriptive Statistics Terms]</ref>