In probability theory and statistics, variance is the expectation of the squared deviation of a random variable from its mean. Informally, it measures. Variance has a central role in statistics, where some ideas that use it include descriptive statistics, statistical inference, hypothesis testing, goodness of fit, Monte Carlo sampling. Variance is an important tool in the sciences; the variance is the square of the standard deviation, the second central moment of a distribution, the covariance of the random variable with itself, it is represented by σ 2, s 2, or Var ⁡. The variance of a random variable X is the expected value of the squared deviation from the mean of X, μ = E ⁡: Var ⁡ = E ⁡; this definition encompasses random variables that are generated by processes that are discrete, neither, or mixed. The variance can be thought of as the covariance of a random variable with itself: Var ⁡ = Cov ⁡; the variance is equivalent to the second cumulant of a probability distribution that generates X.

The variance is designated as Var ⁡, σ X 2, or σ 2. The expression for the variance can be expanded: Var ⁡ = E ⁡ = E ⁡ = E ⁡ − 2 E ⁡ E ⁡ + E ⁡ 2 = E ⁡ − E ⁡ 2 In other words, the variance of X is equal to the mean of the square of X minus the square of the mean of X; this equation should not be used for computations using floating point arithmetic because it suffers from catastrophic cancellation if the two components of the equation are similar in magnitude. There exist numerically stable alternatives. If the generator of random variable X is discrete with probability mass function x 1 ↦ p 1, x 2 ↦ p 2, …, x n ↦ p n Var ⁡ = ∑ i = 1 n p i ⋅ 2, or equivalently Var ⁡ = − μ 2, {\displaystyle \op

Binary chemical weapons or munitions are chemical weapons which contain the toxic agent in its active state as chemical precursors which are less toxic than the agent. This improves the safety of storing and disposing of the weapon. Firing the munition removes a barrier between two precursors; these react to form the intended agent, aerosolized and distributed by a bursting charge. Binary chemical weapons are chemical weapons within the scope of the Chemical Weapons Convention and therefore their production and stockpiling is forbidden in most countries, as at least one of the individual chemicals is to be a Schedule 1 chemical for which large scale production is forbidden. One example of a binary chemical weapon is the United States Army M687. In the M687, methylphosphonyl difluoride and a mixture of two agents held in chambers within the munition, separated by a partition; when the weapon is fired, acceleration causes the partition to break, the precursors are mixed by the rotation of the munition in flight, producing sarin nerve agent.

The Soviet Union and Russian Federation experimented with binary munitions capable of mixing and distributing two agents that would work together in worsening the weapon's effects, an example of which would be the combination of nerve agents with blister agents. The director of a non-proliferation research program of the Middlebury Institute of International Studies at Monterey has stated that the death of Kim Jong-nam due to poisoning with VX was carried out with a binary version of the agent, since VX fumes would otherwise have killed the suspected attackers. A miniature binary weapon is used in an assassination in the Frederick Forsyth novel The Devil's Alternative, it consists of two half-capsules, a non-resistant one containing potassium cyanide and an acid-resistant one containing hydrochloric acid. The substances mix after the halves are assembled and the seal between them is broken, form hydrogen cyanide; the surplus acid eats through the capsule walls of the non-resistant half, after a delay of several hours, the lethal content is released into the intestinal tract of whoever ingested it.

While technically possible, the assassination tool as discussed in the novel is fictional. However, there are claims that in September 2003, the SVR prepared to assassinate Boris Berezovsky with a similar device. In the 10th and 11th episodes of the 6th season of TV-series Dexter are shown preparation and application of binary weapon consisting of two containers filled with DF and isopropyl alcohol; when mixed, the two substances form sarin. The 2002 movie xXx features a Soviet-made binary chemical weapon codenamed "Silent Night", after its supposed ability to render an area silent by killing its inhabitants. In the movie, the chemical was acquired by the terrorist group Anarchy-99, their leader, plans to launch missiles containing Silent Night from an autonomous solar-powered submarine called Ahab, with the intent to sow chaos among civilized nations as they all blame each other for the attacks. Binary liquid QL Mubtakkar Binary explosive Goldfarb, Alexander & Litvinenko, Marina: Death of a dissident: The Poisoning of Alexander Litvinenko and the Return of the KGB.

The Free Press. ISBN 1-4165-5165-4

Love Is the Evidence is the first studio album by the Christian rock band Citizen Way, released on April 26, 2013 by Fair Trade Services, the producers on the album were Seth Mosley and Citizen Way. Love Is the Evidence has received universal acclaim from the music critics. Louder Than the Music's Dave Wood found the release to be "modern and relevant sounding, with stunning moments of brilliant inspiration", which "their pop approach to worship is refreshing and entertaining". At New Release Tuesday, Kevin Davis told that after hearing the album he was "stirred with compassion to love people as Jesus loves us." At Cross Rhythms, Tony Cummings touched on that it took nine years for the band to come into the spotlight, now "their radio-friendly music will mean they stay in the spotlight for quite awhile." At CCM Magazine, Grace S. Aspinwall noted how "listeners will gravitate towards the likeable pop sound that Citizen Way bring to the table", this makes it a "strong and enjoyable album and promising debut from start to finish."

Mark Rice of Jesus Freak Hideout alluded to how the release was "pretty good with greatness within its grasp." Christian Music Zine's Emily Kjonaas evoked that she "see a lot of potential for this band of brothers." At Indie Vision Music, Jonathan Andre vowed that "while it does have its mishaps and drama, is far from unfixable with a great amount of potential to improve upon in years to come!" On the May 11, 2013 charts, the album was the fourth most sold Billboard Top Heatseekers album. Plus, it was the No. 22 most sold Christian Album in the United States