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|Use in other languages|
Beta (UK: /ˈbiːtə/, US: /ˈbeɪtə/; uppercase Β, lowercase β, or cursive ϐ; Ancient Greek: βῆτα, romanized: bē̂ta or Greek: βήτα, romanized: víta) is the second letter of the Greek alphabet. In the system of Greek numerals, it has a value of 2. In Ancient Greek, beta represented the voiced bilabial plosive IPA: [b]. In Modern Greek, it represents the voiced labiodental fricative IPA: [v] (while IPA: [b] in foreign words is instead commonly transcribed as μπ). Letters that arose from beta include the Roman letter ⟨B⟩ and the Cyrillic letters ⟨Б⟩ and ⟨В⟩.
Like the names of most other Greek letters, the name of beta was adopted from the acrophonic name of the corresponding letter in Phoenician, which was the common Semitic word *bait ('house'). In Greek, the name was βῆτα bêta, pronounced [bɛ̂ːta] in Ancient Greek. It is spelled βήτα in modern monotonic orthography and pronounced [ˈvita].
The letter beta was derived from the Phoenician letter beth .
The letter Β had the largest number of highly divergent local forms. Besides the standard form (either rounded or pointed, ), there were forms as varied as (Gortyn), and (Thera), (Argos), (Melos), (Corinth), (Megara, Byzantium), and (Cyclades).
In the system of Greek numerals, beta has a value of 2. Such use is denoted by a number mark: Β′.
Beta is used in finance as a measure of (historical; pseudo-implied) financial asset sensitivity to the relevant benchmark index. Conditional on the benchmark index, the resulting beta value can vary considerably (S&P500 vs NASDAQ vs ETF of a specific industry).
Beta should not to be confused with standard deviation (or the semi-variance, which considers only negative returns): the preferred measure of the "riskiness" (historical volatility of returns) of a financial asset or a portfolio in isolation.
Beta can be calculated as the covariance of a financial asset (or portfolio) with its benchmark index, divided by the variance of the benchmark index. Since the industry of finance gravitates towards return generating activities, typically the historical returns (percentage changes) are used in the calculations Beta values (among others). There are numerous other methods a financial analyst can employ to derive Beta values if historical prices are not available. Beta values change over time (company restructuring; industry sentiment; endo/exogenous factors). Beta values also vary, conditional on the time period used in calculating a Beta value. Beta values can be negative, which infers the existence of financial assets which historically, tended to move in opposite directions to one another by some unit value. It would seem these are the optimal "hedges" to offset market-draw-downs, during periods of market-stress and poor liquidity Beta values can vary dramatically, and previously low or even negative correlations converge to "1".
A beta of 1.5 implies that for every 1% change in the value of the benchmark index, the portfolio's value tends to change by 1.5%. The greater the absolute value, the greater the implied move.
International Phonetic Alphabet
In the International Phonetic Alphabet, Greek minuscule beta denotes a voiced bilabial fricative [β].
A superscript version may also indicate a compressed vowel, like [ɯᵝ].
Beta has twice been used to name an Atlantic Basin tropical cyclone:
- Hurricane Beta, in 2005
- Tropical Storm Beta, in 2020
Mathematics and science
Beta is often used to denote a variable in mathematics and physics, where it often has specific meanings for certain applications. In physics a stream of unbound energetic electrons is commonly referred to as beta radiation or beta rays. Decays producing electrons or their antiparticles are called beta decays. In regression analysis, ⟨B⟩ symbolizes nonstandardized partial slope coefficients, whereas ⟨β⟩ represents standardized (standard deviation-score form) coefficients; in both cases, the coefficients reflect the change in the criterion Y per one-unit change in the value of the associated predictor X. β is also used in biology, for instance in β-Carotene, a primary source of provitamin A, or the β cells in pancreatic islets, which produce insulin.
β is sometimes used as a placeholder for an ordinal number if α is already used. For example, the two roots of a quadratic equation are typically labelled α and β.
In spaceflight, beta angle describes the angle between the orbit plane of a spacecraft or other body and the vector from the sun.
β is sometimes used to mean the proton-to-electron mass ratio.
Rock climbing terminology
The term "beta" refers to advice on how to successfully complete a particular climbing route, boulder problem, or crux sequence.
Beta male, or simply beta, is a slang term for men derived from the designation for beta animals in ethology, along with its counterpart, alpha male. The term has been used as a pejorative self-identifier among members of manosphere communities, particularly incels, who do not believe they are assertive or traditionally masculine, and feel overlooked by women. It is also used to negatively describe other men who are not assertive, particularly in heterosexual relationships.
In statistics, beta may represent type II error, or regression slope.
In some high-quality typesetting, especially in the French tradition, a typographic variant of the lowercase letter without a descender is used within a word for ancient Greek: βίβλος is printed βίϐλος.
In typesetting technical literature, it is a commonly made mistake to use the German letter ß (a s–z or s–s ligature) as a replacement for β. The two letters resemble each other in some fonts, but they are unrelated.
"Beta" can be used to refer to several consumer and professional videotape formats developed by Japan's Sony Corporation. Although similarly named, they are very different in function and obsolescence.
- Betamax was the name of a domestic videotape format developed in the 1970s and 1980s. It competed with the Video Home System (VHS) format developed by the Japanese Victor Company, to which it eventually succumbed. The Betamax format was also marketed Betacord by (Sanyo); some cassettes were simply labeled "Beta", and the logo was a lower-case beta. Betamax lost in the market and is an oft-used example of a technically superior solution that failed due to market forces.
- Betacam, including Beta SP and DigiBeta, is a family of professional videotape formats launched in 1982 that was the de facto standard for professional video, advertising, and television production through the 2000s. The formats outlasted analog NTSC television, and their scarcity today is because the industry has moved to HD formats.
- Greek Beta
|Unicode name||GREEK CAPITAL LETTER BETA||GREEK SMALL LETTER BETA||GREEK BETA SYMBOL||MODIFIER LETTER SMALL BETA||GREEK SUBSCRIPT SMALL LETTER BETA|
|UTF-8||206 146||CE 92||206 178||CE B2||207 144||CF 90||225 181 157||E1 B5 9D||225 181 166||E1 B5 A6|
|Numeric character reference||Β
|Named character reference||Β||β|
|Unicode name||LATIN CAPITAL LETTER BETA||LATIN SMALL LETTER BETA|
|UTF-8||234 158 180||EA 9E B4||234 158 181||EA 9E B5|
|Numeric character reference||Ꞵ
- Mathematical Beta
|Unicode name||MATHEMATICAL BOLD
|MATHEMATICAL BOLD ITALIC
|MATHEMATICAL BOLD ITALIC|
|UTF-8||240 157 154 169||F0 9D 9A A9||240 157 155 131||F0 9D 9B 83||240 157 155 163||F0 9D 9B A3||240 157 155 189||F0 9D 9B BD||240 157 156 157||F0 9D 9C 9D||240 157 156 183||F0 9D 9C B7|
|UTF-16||55349 57001||D835 DEA9||55349 57027||D835 DEC3||55349 57059||D835 DEE3||55349 57085||D835 DEFD||55349 57117||D835 DF1D||55349 57143||D835 DF37|
|Numeric character reference||𝚩
|Unicode name||MATHEMATICAL SANS-SERIF
BOLD CAPITAL BETA
BOLD SMALL BETA
BOLD ITALIC CAPITAL BETA
BOLD ITALIC SMALL BETA
|UTF-8||240 157 157 151||F0 9D 9D 97||240 157 157 177||F0 9D 9D B1||240 157 158 145||F0 9D 9E 91||240 157 158 171||F0 9D 9E AB|
|UTF-16||55349 57175||D835 DF57||55349 57201||D835 DF71||55349 57233||D835 DF91||55349 57259||D835 DFAB|
|Numeric character reference||𝝗
These characters are used only as mathematical symbols. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style.
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