Accuracy and precision in the context of Micrometer (device)

Modern competitive archery involves shooting arrows at a target for accuracy and precision from a set distance or distances. This is the most popular form of competitive archery worldwide and is called target archery. A form particularly popular in Europe, North America, and South America is field archery, shot at targets generally set at various distances in a wooded setting. There are also several other lesser-known and historical forms, as well as archery novelty games.

The World Archery Federation (WA, also and formerly known as FITA from the French Fédération Internationale de Tir à l'Arc), composed of 156 national federations and other archery associations, is the governing body recognized by the International Olympic Committee. Various other large organizations exist with different rules.

Test validity is the extent to which a test (such as a chemical, physical, or scholastic test) accurately measures what it is supposed to measure. In the fields of psychological testing and educational testing, "validity refers to the degree to which evidence and theory support the interpretations of test scores entailed by proposed uses of tests". Although classical models divided the concept into various "validities" (such as content validity, criterion validity, and construct validity), the currently dominant view is that validity is a single unitary construct.

Validity is generally considered the most important issue in psychological and educational testing because it concerns the meaning placed on test results. Though many textbooks present validity as a static construct, various models of validity have evolved since the first published recommendations for constructing psychological and education tests. These models can be categorized into two primary groups: classical models, which include several types of validity, and modern models, which present validity as a single construct. The modern models reorganize classical "validities" into either "aspects" of validity or "types" of validity-supporting evidence

In mathematical optimization and computer science, heuristic (from Greek εὑρίσκω eurísko "I find, discover") is a technique designed for problem solving more quickly when classic methods are too slow for finding an exact or approximate solution, or when classic methods fail to find any exact solution in a search space. This is achieved by trading optimality, completeness, accuracy, or precision for speed. In a way, it can be considered a shortcut.

A heuristic function, also simply called a heuristic, is a function that ranks alternatives in search algorithms at each branching step based on available information to decide which branch to follow. For example, it may approximate the exact solution.

A pipette (sometimes spelled as pipet) is a type of laboratory tool commonly used in chemistry and biology to transport a measured volume of liquid, often as a media dispenser. Pipettes come in several designs for various purposes with differing levels of accuracy and precision, from single piece glass pipettes to more complex adjustable or electronic pipettes. Many pipette types work by creating a partial vacuum above the liquid-holding chamber and selectively releasing this vacuum to draw up and dispense liquid. Measurement accuracy varies greatly depending on the instrument.

Real-time kinematic positioning (RTK) is the application of surveying to correct for common errors in current satellite navigation (GNSS) systems. It uses measurements of the phase of the signal's carrier wave in addition to the information content of the signal and relies on a single reference station or interpolated virtual station to provide real-time corrections, providing up to centimetre-level accuracy (see DGPS). With reference to GPS in particular, the system is commonly referred to as carrier-phase enhancement, or CPGPS. It has applications in land surveying, hydrographic surveying, and in unmanned aerial vehicle navigation.

A varmint rifle or varminter is a type of small-caliber, precision-oriented long gun (firearm or high-powered airgun) primarily used for varmint hunting and pest control. Such rifles are typically characterized by sniper rifle-like designs such as heavy free-floating barrel, enhanced bedding, ergonomic gunstock, the use of bipod/beanbag and high-power telescopic sight, and the choice of high-muzzle velocity, high-ballistic coefficient munitions, which are all accurizing features needed for improving repeated shooting, often over long distances.

Both varmint hunting (which eliminates harassing outdoor nuisance animals collectively called varmints) and pest control (which removes infestations of destructive, often indoor pests) typically target animals that are difficult to eradicate by conventional hunting techniques due to their sheer numbers, burrowing or escape behaviors, camouflaging and defilading by the surroundings, or long alert distances that prevent easy approach or detection. These target animals typically come in three groups:

Isotopic reference materials are compounds (solids, liquids, gasses) with well-defined isotopic compositions and are the ultimate sources of accuracy in mass spectrometric measurements of isotope ratios. Isotopic references are used because mass spectrometers are highly fractionating. As a result, the isotopic ratio that the instrument measures can be very different from that in the sample's measurement. Moreover, the degree of instrument fractionation changes during measurement, often on a timescale shorter than the measurement's duration, and can depend on the characteristics of the sample itself. By measuring a material of known isotopic composition, fractionation within the mass spectrometer can be removed during post-measurement data processing. Without isotope references, measurements by mass spectrometry would be much less accurate and could not be used in comparisons across different analytical facilities. Due to their critical role in measuring isotope ratios, and in part, due to historical legacy, isotopic reference materials define the scales on which isotope ratios are reported in the peer-reviewed scientific literature.

Isotope reference materials are generated, maintained, and sold by the International Atomic Energy Agency (IAEA), the National Institute of Standards and Technology (NIST), the United States Geologic Survey (USGS), the Institute for Reference Materials and Measurements (IRMM), and a variety of universities and scientific supply companies. Each of the major stable isotope systems (hydrogen, carbon, oxygen, nitrogen, and sulfur) has a wide variety of references encompassing distinct molecular structures. For example, nitrogen isotope reference materials include N-bearing molecules such ammonia (NH₃), atmospheric dinitrogen (N₂), and nitrate (NO₃). Isotopic abundances are commonly reported using the δ notation, which is the ratio of two isotopes (R) in a sample relative to the same ratio in a reference material, often reported in per mille (‰) (equation below). Reference material span a wide range of isotopic compositions, including enrichments (positive δ) and depletions (negative δ). While the δ values of references are widely available, estimates of the absolute isotope ratios (R) in these materials are seldom reported. This article aggregates the δ and R values of common and non-traditional stable isotope reference materials.

Rounding or rounding off is the process of adjusting a number to an approximate, more convenient value, often with a shorter or simpler representation. For example, replacing $23.4476 with $23.45, the fraction 312/937 with 1/3, or the expression √2 with 1.414.

Rounding is often done to obtain a value that is easier to report and communicate than the original. Rounding can also be important to avoid misleadingly precise reporting of a computed number, measurement, or estimate; for example, a quantity that was computed as 123456 but is known to be accurate only to within a few hundred units is usually better stated as "about 123500".

In shooting sports, a shot grouping, or simply group, is the collective pattern of projectile collisions (i.e. ballistic impacts) on a shooting target from multiple consecutive shots taken in one shooting session. The tightness of the grouping (the proximity of all the shots to each other) is a measure of the precision of the launching weapon, and a measure of the shooter's consistency and skill. On the other hand, the grouping's displacement (the distance between the calculated group center and the intended point of aim) is a measure of accuracy.

Tightness of shot groupings are calculated by measuring the maximum distance between any two bullet holes on the target (center-to-center) in length measurements such as millimeters or inches. Often that measurement is converted into angular measurements such as milliradians ("mils" or "mrads") or minutes of angle (MOAs), which expresses the size of shot scatter regardless of the target distance. Thus, by using angular measurements, one can reliably compare the relative tightness of shot groupings fired at different distances.

In analytical chemistry, a standard solution (titrant or titrator) is a solution containing an accurately known concentration. Standard solutions are generally prepared by dissolving a solute of known mass into a solvent to a precise volume, or by diluting a solution of known concentration with more solvent. A standard solution ideally has a high degree of purity and is stable enough that the concentration can be accurately measured after a long shelf time.

Making a standard solution requires great attention to detail to avoid introducing any risk of contamination that could diminish the accuracy of the concentration. For this reason, glassware with a high degree of precision such as a volumetric flask, volumetric pipette, micropipettes, and automatic pipettes are used in the preparation steps. The solvent used must also be pure and readily able to dissolve the solute into a homogenous solution.

A frequency standard is a stable oscillator used for frequency calibration or reference. A frequency standard generates a fundamental frequency with a high degree of accuracy and precision. Harmonics of this fundamental frequency are used to provide reference points.

Since time is the reciprocal of frequency, it is relatively easy to derive a time standard from a frequency standard. A standard clock comprises a frequency standard, a device to count off the cycles of the oscillation emitted by the frequency standard, and a means of displaying or outputting the result.

Louis Essen OBE FRS (6 September 1908 – 24 August 1997) was an English physicist whose most notable achievements were in the precise measurement of time and the determination of the speed of light. He was a critic of Albert Einstein's theory of relativity, particularly as it related to time dilation.

Circular error probable (CEP), also circular error probability or circle of equal probability, is a measure of a weapon system's precision in the military science of ballistics. It is defined as the radius of a circle, centered on the aimpoint, that is expected to enclose the landing points of 50% of the rounds; said otherwise, it is the median error radius, which is a 50% confidence interval. That is, if a given munitions design has a CEP of 10 m, when 100 munitions are targeted at the same point, an average of 50 will fall within a circle with a radius of 10 m about that point.

An associated concept, the DRMS (distance root mean square), calculates the square root of the average squared distance error, a form of the standard deviation. Another is the R95, which is the radius of the circle where 95% of the values would fall, a 95% confidence interval.

A designated marksman rifle (DMR) is a modern scoped high-precision rifle used by infantry in the designated marksman (DM) role. It generally fills the engagement range gap between a service rifle and a dedicated sniper rifle, at around 300–600 metres (330–660 yd).

DMRs are distinguished from sniper rifles in that they are semi-automatic to provide higher rates of fire (with some also having selective fire to switch to burst or automatic) and have larger magazine capacities (10, 20, or 30 rounds depending on the firearm and operational requirements) to allow rapid engagement of multiple targets.