Statistics is a branch of mathematics dealing with the collection, analysis, interpretation, presentation, and organization of data. In applying statistics to, e.g., a scientific, industrial, or social problem, it is conventional to begin with a statistical population or a statistical model process to be studied. Populations can be diverse topics such as "all people living in a country" or "every atom composing a crystal". Statistics deals with all aspects of data including the planning of data collection in terms of the design of surveys and experiments.
Some popular definitions are:
Merriam-Webster dictionary defines statistics as "a branch of mathematics dealing with the collection, analysis, interpretation, and presentation of masses of numerical data"".
Statistician Sir Arthur Lyon Bowley defines statistics as "Numerical statements of facts in any department of inquiry placed in relation to each other".
When census data cannot be collected, statisticians collect data by developing specific experiment designs and survey samples. Representative sampling assures that inferences and conclusions can safely extend from the sample to the population as a whole. An experimental study involves taking measurements of the system under study, manipulating the system, and then taking additional measurements using the same procedure to determine if the manipulation has modified the values of the measurements. In contrast, an observational study does not involve experimental manipulation.
Two main statistical methods are used in data analysis: descriptive statistics, which summarizes data from a sample using indexes such as the mean or standard deviation, and inferential statistics, which draws conclusions from data that are subject to random variation (e.g., observational errors, sampling variation). Descriptive statistics are most often concerned with two sets of properties of a distribution (sample or population): central tendency (or location) seeks to characterize the distribution's central or typical value, while dispersion (or variability) characterizes the extent to which members of the distribution depart from its center and each other. Inferences on mathematical statistics are made under the framework of probability theory, which deals with the analysis of random phenomena.
A standard statistical procedure involves the test of the relationship between two statistical data sets, or a data set and a synthetic data drawn from idealized model. A hypothesis is proposed for the statistical relationship between the two data sets, and this is compared as an alternative to an idealized null hypothesis of no relationship between two data sets. Rejecting or disproving the null hypothesis is done using statistical tests that quantify the sense in which the null can be proven false, given the data that are used in the test. Working from a null hypothesis, two basic forms of error are recognized: Type I errors (null hypothesis is falsely rejected giving a "false positive") and Type II errors (null hypothesis fails to be rejected and an actual difference between populations is missed giving a "false negative"). Multiple problems have come to be associated with this framework: ranging from obtaining a sufficient sample size to specifying an adequate null hypothesis.
Measurement processes that generate statistical data are also subject to error. Many of these errors are classified as random (noise) or systematic (bias), but other types of errors (e.g., blunder, such as when an analyst reports incorrect units) can also be important. The presence of missing data or censoring may result in biased estimates and specific techniques have been developed to address these problems.
Statistics can be said to have begun in ancient civilization, going back at least to the 5th century BC, but it was not until the 18th century that it started to draw more heavily from calculus and probability theory. Statistics continues to be an area of active research, for example on the problem of how to analyze Big data.

View More On
  1. Jim Colvill

    National  Gun rights are winning and nobody has realized it.

    A fascinating and informative read. Spend about 20 minutes to read. Gun rights are winning and nobody has realized it | Open Source Defense
  2. prkrgrp


    So there is finally some statistics from the 6 year study from Utahs coyote bounty. Officials are unable to see any real effects from the bounty program which has paid out over half a million dollars and claims over 91,000 coyotes were turned in during the last six years, when you add in the...
  3. Hawaiian

    Concealed Carry Statistics

    Interesting nation wide stats by State. Just scroll down the page to see all the different stats. Concealed Carry Statistics: Quick Facts by State (2017)
  4. ob1

    Member profile statistics ?

    Like many, I make frequent use of the posted statistics found in member's profile columns. It's handy to see what a particular member's selling feedback and length of membership is when, for example, browsing an item in the classifieds. There is one statistic that I notice from time to time...
  5. Joe Link

    National  News Media Distort Statistics on US Firearms Ownership and Mass Shootings, Gun Expert Lott Says

    News Media Distort Statistics on US Firearms Ownership and Mass Shootings, Gun Expert Lott Says
  6. Hawaiian

    Oregon Background Check Statistics.

    Here is a pretty detailed report on firearm background checks in Oregon.
Back Top