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  2. Minute and second of arc - Wikipedia

    en.wikipedia.org/wiki/Minute_and_second_of_arc

    A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol ′, is a unit of angular measurement equal to ⁠ 1 / 60 ⁠ of one degree. [1] Since one degree is ⁠ 1 / 360 ⁠ of a turn, or complete rotation, one arcminute is ⁠ 1 / 21 600 ⁠ of a turn.

  3. Milliradian - Wikipedia

    en.wikipedia.org/wiki/Milliradian

    A milliradian (SI-symbol mrad, sometimes also abbreviated mil) is an SI derived unit for angular measurement which is defined as a thousandth of a radian (0.001 radian). ). Milliradians are used in adjustment of firearm sights by adjusting the angle of the sight compared to the barrel (up, down, left, or

  4. Angular diameter - Wikipedia

    en.wikipedia.org/wiki/Angular_diameter

    Degrees, therefore, are subdivided as follows: 360 degrees (°) in a full circle; 60 arc-minutes (′) in one degree; 60 arc-seconds (″) in one arc-minute; To put this in perspective, the full Moon as viewed from Earth is about 1 ⁄ 2 °, or 30 ′ (or 1800″). The Moon's motion across the sky can be measured in angular size: approximately ...

  5. Equation of time - Wikipedia

    en.wikipedia.org/wiki/Equation_of_time

    The correct branch of the multiple valued function arctan x to use is the one that makes ν a continuous function of E(M) starting from ν E=0 = 0. Thus for 0 ≤ E < π use arctan x = arctan x, and for π < E ≤ 2π use arctan x = arctan x + π. At the specific value E = π for which the argument of tan is infinite, use ν = E.

  6. Kurtosis - Wikipedia

    en.wikipedia.org/wiki/Kurtosis

    Setting a 2 = 2m − 3 makes the variance equal to unity. Then the only free parameter is m , which controls the fourth moment (and cumulant) and hence the kurtosis. One can reparameterize with m = 5 / 2 + 3 / γ 2 {\displaystyle m=5/2+3/\gamma _{2}} , where γ 2 {\displaystyle \gamma _{2}} is the excess kurtosis as defined above.

  7. Student's t-distribution - Wikipedia

    en.wikipedia.org/wiki/Student's_t-distribution

    Let's say we have a sample with size 11, sample mean 10, and sample variance 2. For 90% confidence with 10 degrees of freedom, the one-sided t value from the table is 1.372 . Then with confidence interval calculated from

  8. Visual acuity - Wikipedia

    en.wikipedia.org/wiki/Visual_acuity

    [4] [5] The decline is according to E 2 /(E 2 +E), where E is eccentricity in degrees visual angle, and E 2 is a constant of approximately 2 degrees. [ 4 ] [ 6 ] [ 7 ] At 2 degrees eccentricity, for example, acuity is half the foveal value.

  9. Quartz crystal microbalance - Wikipedia

    en.wikipedia.org/wiki/Quartz_crystal_microbalance

    Here Z F is the acoustic impedance of the film (Z F = ρ F c F = (ρ F G f) 1/2)= (ρ F /J f) 1/2), k F is the wave vector and d F is the film thickness. J f is the film's viscoelastic compliance, ρ F is the density. The poles of the tangent (k F d F = π/2) define the film resonances. [55] [56] At the film resonance, one has d F = λ/4. The ...