# Arithmetic average

It would be unrealistic to represent the porosity of the sand as the arithmetic average of the measured values (0.20), since this would ignore the range of measured values, the volumes which each of the measurements may be assumed to represent, and the possibility that the porosity may move outside the range away from the control points. There appears to be a trend of decreasing porosity to the south-east, and the end points of the range may be 0.25 and 0.15, i.e. larger than the range of measurements made. An understanding of the geological environment of deposition and knowledge of any diagenetic effects would be required to support this hypothesis, but it could only be proven by further data gathering in the extremities of the field. [c.159]

Two kinds of octane number ratings are specified, although other methods are often used for engine and fuel development. Both methods use the same reference fuels and essentially the same test engine, but engine operating conditions are different. In one test, called the research method, the spark advance is fixed, the air inlet temperature is 125°F (—52°C), and engine speed is 600 r/min. The other, called the motor method, uses variable spark timing, a higher mixture temperature of 300°F (—149°C), and a faster engine speed of 900 r/min. The more severe conditions of the motor method have a greater influence on commercial blends than they do on the reference fuels. Thus, the motor octane number of a commercial blend tends to be lower than the research octane number. Common practice is to label gasoline with an arithmetic average of both ratings, abbreviated as (R + M/2, and often referred to as road octane number. [c.210]

The sample mean corresponds to the arithmetic average of the observations, which will be designated as Xi through a.(3, where [c.488]

Wilke obtained solutions to the Stefan-Maxwell equations. The first, Eq. (5-206), is simple and rehable under the same conditions as Blanc s law. This equation apphes when component i diffuses through a stagnant mixture. It has been tested and verified for diffusion of toluene in hydrogen -i- air -i- argon mixtures and for diffusion of ethyl propionate in hydrogen -i- air mixtures (Fairbanks and Wilke). When the compositions vaiy from one boundaiy to the other, Wilke recommends that the arithmetic average mole fractions be used. Wilke also suggested using the Stefan-Maxwell equation, which applies when the fluxes of two or more components are significant. In this situation, the mole fractions are arithmetic averages of the boundary conditions, and the solution requires iteration because the ratio or fluxes is not known a priori. [c.596]

The standard deviation. s° for the sample corresponds to the true standard deviation O for the whole population in the same way that the mean x of the sample corresponds to the arithmetic average [L for the whole population. Equation (9-70) can be written more compactly as [c.822]

Thermal Conductivity (K Factor) Depending on the type of insulation, the thermal conductivity K factor) can vary with age, manufacturer, moisture content, and temperature. Typical published values are shown in Fig. 11-65. Mean temperature is equal to the arithmetic average of me temperatures on both sides of the insulating material. [c.1098]

The line current in each phase of the motor should be measured. If the line current is not exactly equal in all phases, the arithmetical average of the phase current must be tised for calculating the machine s performance. [c.251]

The 5 value, which is called the median value, is not necessarily the same as the average value, which is also called the arithmetic mean value. The arithmetic average value is obtained by adding all 8760 values and then dividing the total by 8760. The arithmetic average value obtained for other averaging times, e.g., by adding all 365 24-hr values and dividing [c.53]

The arithmetic average of the tube pass ATm s is the ATm corrected for number of passes. F = ATm cor-rected/ATM unconnected. [c.29]

Mean in occupied zone T he arithmetic average of the measured values of air temperature in the occupied zone. [c.1480]

The bulk fluid temperature at which the fluid properties are obtained should be the average temperature between the fluid inlet and outlet temperatures. The viscosity at the tube wall should be the fluid viscosity at the arithmetic average temperature between the inside fluid bulk temper- [c.17]

Mean The measure of central tendency of a distribution, often referred to as its arithmetic average. [c.287]

Calculate (1 - y)M. arithmetic average of non-diffusing gas concentration at ends of diffusing path [c.349]

Sometimes one of the fluid-side scale resistances can be neglected or assumed to be so small as to be of little value, in which case only the significant resistances and/or film coefficients need to be used in arriving at the overall coefficient, U. Note that Aq, Aj, and can be substituted by d , dit, and d g respectively. Theoretically, d g and should be the logarithmic average, but for most practical cases, the use of the arithmetic average is completely satisfactory. [c.88]

Note that the arithmetic average [Vj (176 — 105) + 105 = 140°F] would be quite satisfactory for this design, because the properties do not vary significantly with temperature. [c.112]

The correlation of Akers, et. al., has given good results in some industrial designs. The authors report that some vertical and inclined tube data is also correlated on the same basis. The sharp break in the data occurs around a Reynolds number of 5 X lO as shown in Figure 10-75. The mass flow rate used to correlate is the arithmetic average of inlet and oudet liquid condensate and vapor flows [c.130]

Gl and Gg = arithmetic averages of condensate and vapor flow respectively, Ib/hr (ft of flow cross section) [c.130]

Choose an increment of vaporization, starting at the end of the sensible heating zone. Use the arithmetic average value of x for increment calculations. The circulation rate already obtained on the basis of average conditions should be used for initial calculations. [c.184]

Determine the heat duty by the usual procedures and define the boiling temperature on the shell side. Determine the arithmetic average of tube side temperature, t,. [c.226]

Arithmetic average tube-side temperature. [c.227]

Raw data are collected observations that have not been organized numerically. An average is a value that is typical or representative of a set of data. Several averages can be defined, the most common being the arithmetic mean (or briefly, the mean), the median, the mode, and the geometric mean. [c.192]

Crude petroleum is fractionated into around fifty cuts having a very narrow distillation intervals which allows them to be considered as ficticious pure hydrocarbons whose boiling points are equal to the arithmetic average of the initial and final boiling points, = (T, + Ty)/2, the other physical characteristics being average properties measured for each cut. [c.331]

The separative capacity of the equivalent theoretical stage in the continuous process is seen to depend on the concentration difference between the countercurrent streams as well as on the concentration difference between the top and bottom of the stage. The separative capacity is zero when V is equal tojy or V is equal to x inspection shows that it attains a maximum value when V is equal to the arithmetic average of x andjy and that this maximum value [c.77]

The mean x is the statistic corresponding to the population parameters I, which is the arithmetic average of all the items in the popiila- [c.821]

The voltage must approach a sinusoidal waveform and should be balanced. If at the time of conducting the tests the voltage is almost btit not completely balaticeil. arithmetical average of the phase volttige must be used for calculating the machine s performance. [c.251]

The gear teeth should be heat-treated for proper strength and through hardened. Alternatively, surface hardening by carburizing or nitriding is used. Flame and induction surface hardening are also alternative hardening methods but normally are used less than carburizing or nitriding. For new gears, through hardening is preferred, using the surface hardening for later upgrades. Requirements for strength and hardness must result in an adequate durability and tooth stress as determined by API 613. The surface finish of the teeth must be 20 microinches Arithmetic Average Roughness Height (Ra) or better. [c.331]

Mechanical profilers, also called profilometers, measure roughness by the mechanical movement of a diamond stylus over the sample of interest. No sample preparation is required and almost any sample that will not be deformed by the stylus can be measured very rapidly. The trace of the surface is typically digitized and stored in a computer for display on a cathode ray tube and for output to a printer. The stylus force can be adjusted to protect delicate surfaces from damage. Typical weight loading ranges from a few milligrams to tens of milligrams, but can be as low as one milligram. Small regions can be located with a microscope or camera mounted on the profiler. Lateral resolution depends upon the stylus radius. If the surface curvature exceeds the radius of curvature of the stylus, then the measurement will not provide a satisfactory reproduction of the surface. A typical stylus radius is about 3 pm, but smaller radii down to even submicron sizes are available. Arithmetic average or root-mean-square roughness can be calculated automatically from the stored array of measurement points. [c.699]

Expert judgement was used to estimate uncertainty distributions for the parameters using the issue definitions with the accident calculations. Expert judgement elicitation used the method of NUREG/CR-4550. Independent panels were not convened the panels consisted of project members and experts familiar with N Reactor, but the fundamental structure of NUREG/CR-4550 was retained i.e., elicitation training and debiasing of the experts, issue decomposition, aggregation of independent elicitations). Typically, participants were asked to consider an issue or parameter. Each analyst established his realistic bounds for the parameter s value. Then, a cumulative probability function (CPF) for the parameter was developed. This might be a well defined probability distribution with mean, standard deviation, and shaping factors, or it might be an empirical CPF characterized by parameters for probability quartiles. The elicitations from analysts were weighted equidly and 2 or 3 individual distributions were arithmetically averaged to yield an aggregated CDF for tlie parameter. [c.425]

Following Metropolis et al. [57], an attempted move is then accepted if a random number, uniformly distributed between zero and one, is less than exp [—SHIk T] where 6H > 0, or simply accepted if < 0 whereby Eq. (7) is automatically fulfilled. Then the configurations generated in this way are distributed proportionally to the equilibrium distribution Feq(X), provided there is no problem with the ergodicity of the algorithm, and the canonical average of any observable is obtained as a simple arithmetic average over the generated configurations. One should keep in mind, however, that the latter does not hold for subsequent configurations which are correlated with each other. Measurements should be performed at intervals comparable to the typical relaxation time of the system. Thus for a simple random walk chain (with no excluded volume interactions) the Rouse model [37] implies that the single chain relaxation time oc which indicates the difficulties encountered when sampling of sufficiently long chains is attempted. [c.562]

Gasolines are the largest volume refiiieiy products. In 199S, for instance, more than 330,000,000 gallons were consumed each day in the United States. This amounts to more than one million tons per day. The best known specifications for gasoline are octane numbers and Reid vapor pressure (RVP). The octanes arc numbers determined by laboratoiy tests and can be related to performance of gasolines at normal road operating conditions. Octane numbers measure the resistance of the gasoline to selUignition (knocking) and are determined by comparison with reference fuels. Self-ignition causes a decrease in engine efficiency and power, and when it occurs there are noticeable reductions in mileage and acceleration. Research octane number can be correlated with city driving performance (RON) and motor octane number (MON) with highway driving performance. Federal regulations require that the arithmetic average of these octanes ([RON + MON]/2) be posted on the pumps dispensing the gasolines. In 1998, about 70 percent of the gasolines sold in the United States were regular grade, and 30 percent premium grades. Regular gasoline posted octanes are 87 for lower elevations and 85 or 86 at higher elevations (above 3,000 feet). The octane requirement of an engine decreases [c.982]

Look up the experimental values of the first ionization potential for these atoms and calculate the average difference between experiment and the computed values. Depending on the source of your experimental data, the arithmetic mean difference should be within 0.010 hartrees. Serious departrues from this level of agreement may indicate that you have one or more of your spin multiplicities wrong. [c.242]

See pages that mention the term

**Arithmetic average**:

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Compressors selections and sizing (1997) -- [ c.0 ]