Chi-squared distributionIn probability theory and statistics, the chi-squared distribution (also chi-square or -distribution) with degrees of freedom is the distribution of a sum of the squares of independent standard normal random variables. The chi-squared distribution is a special case of the gamma distribution and is one of the most widely used probability distributions in inferential statistics, notably in hypothesis testing and in construction of confidence intervals.
Islamic calligraphyIslamic calligraphy is the artistic practice of handwriting and calligraphy, in the languages which use Arabic alphabet or the alphabets derived from it. It includes Arabic, Persian, Ottoman, and Urdu calligraphy. It is known in Arabic as khatt Arabi (خط عربي), which translates into Arabic line, design, or construction. The development of Islamic calligraphy is strongly tied to the Qur'an; chapters and excerpts from the Qur'an are a common and almost universal text upon which Islamic calligraphy is based.
Multivariate normal distributionIn probability theory and statistics, the multivariate normal distribution, multivariate Gaussian distribution, or joint normal distribution is a generalization of the one-dimensional (univariate) normal distribution to higher dimensions. One definition is that a random vector is said to be k-variate normally distributed if every linear combination of its k components has a univariate normal distribution. Its importance derives mainly from the multivariate central limit theorem.
Chinese calligraphyChinese calligraphy is the writing of Chinese characters as an art form, combining purely visual art and interpretation of the literary meaning. This type of expression has been widely practiced in China and has been generally held in high esteem across East Asia. Calligraphy is considered one of the four most-sought skills and hobbies of ancient Chinese literati, along with playing stringed musical instruments, the board game "Go", and painting. There are some general standardizations of the various styles of calligraphy in this tradition.
Sample mean and covarianceThe sample mean (sample average) or empirical mean (empirical average), and the sample covariance or empirical covariance are statistics computed from a sample of data on one or more random variables. The sample mean is the average value (or mean value) of a sample of numbers taken from a larger population of numbers, where "population" indicates not number of people but the entirety of relevant data, whether collected or not. A sample of 40 companies' sales from the Fortune 500 might be used for convenience instead of looking at the population, all 500 companies' sales.
Japanese calligraphyJapanese calligraphy, also called 習字, is a form of calligraphy, or artistic writing, of the Japanese language. Written Japanese was originally based on Chinese characters only, but the advent of the hiragana and katakana Japanese syllabaries resulted in intrinsically Japanese calligraphy styles. The term shodō (書道, "way of writing") is of Chinese origin and is widely used to describe the art of Chinese calligraphy during the medieval Tang dynasty. Early Japanese calligraphy was originated from Chinese calligraphy.
Arabic calligraphyArabic calligraphy is the artistic practice of handwriting and calligraphy based on the Arabic alphabet. It is known in Arabic as khatt (خط), derived from the word 'line', 'design', or 'construction'. Kufic is the oldest form of the Arabic script. From an artistic point of view, Arabic calligraphy has been known and appreciated for its diversity and great potential for development. In fact, it has been linked in the Arabic culture to various fields such as religion, art, architecture, education and craftsmanship, which in return have played an important role in its advancement.
Path integral formulationThe path integral formulation is a description in quantum mechanics that generalizes the action principle of classical mechanics. It replaces the classical notion of a single, unique classical trajectory for a system with a sum, or functional integral, over an infinity of quantum-mechanically possible trajectories to compute a quantum amplitude. This formulation has proven crucial to the subsequent development of theoretical physics, because manifest Lorentz covariance (time and space components of quantities enter equations in the same way) is easier to achieve than in the operator formalism of canonical quantization.
User interfaceIn the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine from the human end, while the machine simultaneously feeds back information that aids the operators' decision-making process. Examples of this broad concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls and process controls.
Euler methodIn mathematics and computational science, the Euler method (also called the forward Euler method) is a first-order numerical procedure for solving ordinary differential equations (ODEs) with a given initial value. It is the most basic explicit method for numerical integration of ordinary differential equations and is the simplest Runge–Kutta method. The Euler method is named after Leonhard Euler, who first proposed it in his book Institutionum calculi integralis (published 1768–1870).
