In descriptive statistics, the interquartile range (IQR) is a measure of statistical dispersion, which is the spread of the data. The IQR may also be called the midspread, middle 50%, fourth spread, or H‑spread. It is defined as the difference between the 75th and 25th percentiles of the data. To calculate the IQR, the data set is divided into quartiles, or four rank-ordered even parts via linear interpolation. These quartiles are denoted by Q1 (also called the lower quartile), Q2 (the median), and Q3 (also called the upper quartile). The lower quartile corresponds with the 25th percentile and the upper quartile corresponds with the 75th percentile, so IQR = Q3 − Q1.
In geometry, a Platonic solid is a convex, regular polyhedron in three-dimensional Euclidean space. Being a regular polyhedron means that the faces are congruent regular polygons, and the same number of faces meet at each vertex. There are only five such polyhedra:
Q, or q, is the seventeenth letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is pronounced, most commonly spelled cue, but also kew, kue and que.
RSA (Rivest–Shamir–Adleman) is a public-key cryptosystem, one of the oldest widely used for secure data transmission. The initialism "RSA" comes from the surnames of Ron Rivest, Adi Shamir and Leonard Adleman, who publicly described the algorithm in 1977. An equivalent system was developed secretly in 1973 at Government Communications Headquarters (GCHQ), the British signals intelligence agency, by the English mathematician Clifford Cocks. That system was declassified in 1997.
Q is a fictional character, as well as the name of a race, in Star Trek, appearing in the Next Generation, Deep Space Nine, Voyager, Lower Decks, and Picard series and in related media. The most familiar Q is portrayed by John de Lancie. He is an extra-dimensional being of unknown origin who possesses immeasurable power over time, space, the laws of physics, and reality itself, being capable of altering it to his whim. Despite his vast knowledge and experience spanning untold eons, he is not above practical jokes for his personal amusement, for a Machiavellian or manipulative purpose, or to prove a point. He is said to be almost completely omnipotent and he is continually evasive regarding his true motivations.
In mathematics, the quaternion number system extends the complex numbers. Quaternions were first described by the Irish mathematician William Rowan Hamilton in 1843 and applied to mechanics in three-dimensional space. The algebra of quaternions is often denoted by H, or in blackboard bold by Quaternions are not a field, because multiplication of quaternions is not, in general, commutative. Quaternions provide a definition of the quotient of two vectors in a three-dimensional space. Quaternions are generally represented in the form
Q fever or query fever is a disease caused by infection with Coxiella burnetii, a bacterium that affects humans and other animals. This organism is uncommon, but may be found in cattle, sheep, goats, and other domestic mammals, including cats and dogs. The infection results from inhalation of a spore-like small-cell variant, and from contact with the milk, urine, feces, vaginal mucus, or semen of infected animals. Rarely, the disease is tick-borne. The incubation period can range from 9 to 40 days. Humans are vulnerable to Q fever, and infection can result from even a few organisms. The bacterium is an obligate intracellular pathogenic parasite.
The second law of thermodynamics is a physical law based on universal empirical observation concerning heat and energy interconversions. A simple statement of the law is that heat always flows spontaneously from hotter to colder regions of matter. Another statement is: "Not all heat can be converted into work in a cyclic process."
Capacitance is the capability of a material object or device to store electric charge. It is measured by the charge in response to a difference in electric potential, expressed as the ratio of those quantities. Commonly recognized are two closely related notions of capacitance: self capacitance and mutual capacitance. An object that can be electrically charged exhibits self capacitance, for which the electric potential is measured between the object and ground. Mutual capacitance is measured between two components, and is particularly important in the operation of the capacitor, an elementary linear electronic component designed to add capacitance to an electric circuit.
In descriptive statistics, a box plot or boxplot is a method for demonstrating graphically the locality, spread and skewness groups of numerical data through their quartiles. In addition to the box on a box plot, there can be lines extending from the box indicating variability outside the upper and lower quartiles, thus, the plot is also called the box-and-whisker plot and the box-and-whisker diagram. Outliers that differ significantly from the rest of the dataset may be plotted as individual points beyond the whiskers on the box-plot. Box plots are non-parametric: they display variation in samples of a statistical population without making any assumptions of the underlying statistical distribution. The spacings in each subsection of the box-plot indicate the degree of dispersion (spread) and skewness of the data, which are usually described using the five-number summary. In addition, the box-plot allows one to visually estimate various L-estimators, notably the interquartile range, midhinge, range, mid-range, and trimean. Box plots can be drawn either horizontally or vertically.
In logic and mathematics, necessity and sufficiency are terms used to describe a conditional or implicational relationship between two statements. For example, in the conditional statement: "If P then Q", Q is necessary for P, because the truth of Q is guaranteed by the truth of P. Similarly, P is sufficient for Q, because P being true always implies that Q is true, but P not being true does not always imply that Q is not true.
Q was a popular music magazine. Originally published in print in the UK from 1986 to 2020, it was inactive from 2020 until 2023. In 2023, Q was revived as an online publication. It was founded in 1986 by broadcast journalists Mark Ellen and David Hepworth, who were presenters of the BBC television music series The Old Grey Whistle Test. Q's final printed issue was published in July 2020, but began posting new articles to their website in 2023 before being fully relaunched in 2024.
Kamaal Ibn John Fareed, better known by his stage name Q-Tip, is an American rapper, record producer, singer, and DJ. Nicknamed the Abstract, he is noted for his innovative jazz-influenced style of hip hop production and his philosophical, esoteric and introspective lyrical themes. He embarked on his music career in the late 1980s, as an MC and main producer of the influential alternative hip hop group A Tribe Called Quest. In the mid-1990s, he co-founded the production team The Ummah, followed by the release of his gold-certified solo debut Amplified in 1999. In the following decade, he released the Grammy Award-nominated album The Renaissance (2008) and the experimental album Kamaal the Abstract (2009).
In linear algebra, a rotation matrix is a transformation matrix that is used to perform a rotation in Euclidean space. For example, using the convention below, the matrix
B&Q Limited is a British multinational DIY and home improvement retailing company, with headquarters in Eastleigh, England. It is a wholly owned subsidiary of Kingfisher plc. It was founded in March 1969 by Richard Block and David Quayle.
QAnon is a far-right American political conspiracy theory and political movement that originated in 2017. QAnon centers on fabricated claims made by an anonymous individual or individuals known as "Q". Those claims have been relayed and developed by online communities and influencers. Their core belief is that a cabal of Satanic, cannibalistic child molesters is operating a global child sex trafficking ring that conspired against president Donald Trump. QAnon has direct roots in Pizzagate, an Internet conspiracy theory that appeared one year earlier, but also incorporates elements of many other theories. QAnon has been described as a cult.
Margaret Denise Quigley, professionally known as Maggie Q, is an American actress.
In cryptography, subliminal channels are covert channels that can be used to communicate secretly in normal looking communication over an insecure channel. Subliminal channels in digital signature crypto systems were found in 1984 by Gustavus Simmons.
Coulomb's inverse-square law, or simply Coulomb's law, is an experimental law of physics that calculates the amount of force between two electrically charged particles at rest. This electric force is conventionally called the electrostatic force or Coulomb force. Although the law was known earlier, it was first published in 1785 by French physicist Charles-Augustin de Coulomb. Coulomb's law was essential to the development of the theory of electromagnetism and maybe even its starting point, as it allowed meaningful discussions of the amount of electric charge in a particle.
The Q source (also called The Sayings Gospel, Q Gospel, Q document(s), or Q; from German: Quelle, meaning "source") is an alleged written collection of primarily Jesus' sayings (λόγια, logia). Q is part of the common material found in the Gospels of Matthew and Luke but not in the Gospel of Mark. According to this hypothesis, this material was drawn from the early Church's oral gospel traditions.
