Pricing errors

To maintain a perpetual inventory system, all purchases and sales must be entered into the computer system (Carroll, 1998 West, 2003). A clerk can enter data from purchases, or the computer dispensing system can be interfaced with the computer order system. The interface allows for the inventory to be reduced when a product is dispensed. The sales data can also be entered at the point of sale by devices that use optical scanning and barcode technology. Point-of-sale (POS) devices are advantageous in that they improve the accuracy of pricing and inventory data. They eliminate the need for price stickers, reduce the frequency of pricing errors, and automatically track inventory. 

There are two essential prerequisites to becoming a successful proactive pricer. First, it is necessary to understand how pricing works. Because of the complexities of pricing in terms of its impact on supphers, salespeople, distributors, competitors, and customers, companies that focirs primarily on their interned costs often make serious pricing errors. 

S = Simplifying operations is shown by special register keys in fast-food operations. The key indicates a specific item ( Big Mac ) rather than a price. This reduces pricing errors and improves communication with the cooking area. For e-mail, the return key simplifies finding the return address and entering it. 

Alternatively, if we think that interest rates will be higher in the future, we can assume a drift factor greater than 0%. In this case, we can calibrate the model yield curve with market yield curve. In other words, we adopt an iterative procedure in which we set the pricing error between the model and market yield curve equal to 0 by changing the drift factor. 

While this also uses a variance-covariance matrix much like the full covariance method, the actual matrix is much more condensed. As an example, the matrix used in a 20-factor model would have a size of (20 X 20) 400 cells, which is moderate compared with the one-million-cell matrix mentioned previously for the full variance-covariance model. The advantages of using a multifactor model are that it easily allows for mapping a new issue into past data for similar bonds by looking at its descriptive characteristics, and it can be inverted for use in a portfolio optimizer without too much effort. The multifactor model is also more tolerant to pricing errors in individual securities since prices are averaged within each factor bucket. 

The FE-based method attempts to address these issues and is less likely to have inherent dangers in providing misleading steam prices than the enthalpy- and exergy-based methods however, it will be more prudent to use the cost-based method if potential pricing errors are to be avoided. This is because the cost-based method can provide accounting values for steam and power, which reflect the tme costs, and the best approach to economic reality. 

There is also a local MP2 (LMP2) method. LMP2 calculations require less CPU time than MP2 calculations. LMP2 is also less susceptible to basis set superposition error. The price of these improvements is that about 98% of the MP2 energy correction is recovered by LMP2. 

Sensitivity Analysis An economic study should pinpoint the areas most susceptible to change. It is easier to predict expenses than either sales or profits. Fairly accurate estimates of capital costs and processing costs can be made. However, for the most part, errors in these estimates have a correspondingly smaller effecl than changes in sales price, sales volume, and the costs of raw materials and distribution. 

If utilities are supplied to the new project from some other source, the cost and amount must be determined. If purchased from a second party, the cost will be determined by contract and can be estimated by discussions with the vendor. If utilities are transferred from an affiliated source, the cost must include a profit to the supplying entity. Some estimators use a lower return on utility plants than on a new hydrocarbon processing unit, since the utility can be used for some alternate plant if the new one shuts down for any reason. However, the preferred analysis allows a high enough utility transfer price to provide the same return on the utilities as the new unit being studied. This can require a trial and error approach, especially if the utilities are a significant part of the selling price of the product. 

Revenues. The selling price for the major product and the quantity to be sold each year must be estimated. If the product is new, this can be a major study. In any case, input is needed from sales, transportation, research, and any other department or individual who can increase the accuracy of the revenue data. The operating costs may be off by 20% without fatal results, but a 20% error in the sales volume or price w ill have a much larger impact. Further, the operating costs are mostly within the control of the operator, while the sales price and volume can be... 

The main characteristics which determine the performance of a wavefront corrector are the number of actuators, actuator stroke and the temporal response. The number of actuators will determine the maximum Strehl ratio which can be obtained with the AO system. The price of a deformable mirror is directly related to the number of actuators. The actuator stroke should be enough to compensate wavefront errors when the seeing is moderately poor. This can be derived from the Noll formula with ao = 1.03. For example, on a 10m telescope with ro = 0.05m at 0.5 m, the rms wavefront error is 6.7 /xm. The deformable mirror stroke should be a factor of at least three times this. It should also include some margin for correction of errors introduced by the telescope itself. The required stroke is too large for most types of deformable mirror, and it is common practice to off-load the tip-tilt component of the wave-front error to a separate tip-tilt mirror. The Noll coefficient a2 = 0.134 and... 

It is important to note that the fitting according to eq. (1) requires zero intercept behavior i.e., F =. 00 for H (for which Oj = Or =. 00). While we recognize that the data for the unsubstituted (H) member of a set may be as subject to experimental error as any other member, such error is generally relatively small for a set of reliable data. Any constant error from this source will be distributed among all of the substituents in such a manner as to achieve best fit. Any loss in precision of fitting of the set which may result by such a procedure we believe is a small price to pay compared to the violence done by introduction in eq. (I) of a completely variable constant parameter. The latter procedure has been utilized by other authors both in treatments by the simple Hammett equation and by the dual substituent parameter equation. 

False negative responses of 0.13-3.2% are an acceptable price. What are the chances of false positives slipping through Four alternative hypotheses are proposed for the VVV scheme (compare p to SL = 99.0, with p = j3, the type II error ) ... 

Note that a number of complicating factors have been left out for clarity For instance, in the EMF equation, activities instead of concentrations should be used. Activities are related to concentrations by a multiplicative activity coefficient that itself is sensitive to the concentrations of all ions in the solution. The reference electrode necessary to close the circuit also generates a (diffusion) potential that is a complex function of activities and ion mobilities. Furthermore, the slope S of the electrode function is an experimentally determined parameter subject to error. The essential point, though, is that the DVM-clipped voltages appear in the exponent and that cheap equipment extracts a heavy price in terms of accuracy and precision (viz. quantization noise such an instrument typically displays the result in a 1 mV, 0.1 mV, 0.01 mV, or 0.001 mV format a two-decimal instrument clips a 345.678. .. mV result to 345.67 mV, that is it does not round up ... 78 to ... 8 ). 

However, because of the high price, MALDI-TOF mass spectrometers have not come into wide use. Vapor pressure osmometry (VPO), an old and traditional method for estimating molecular weight, is useful in the field of CPO chemistry. The experimental error of this measurement is approximately 10% however, the obtained data are sufficiently useful to estimate the number of porphyrins in a molecule. 

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