Recording errors

There are potential errors or problems that limit the accuracy of this alignment technique. The common ones include data recording errors, failure to correct for indicator sag, mechanical looseness in the fixture installation, and failure to properly zero and/or calibrate the dial indicator. 

Most of the optical-alignment systems incorporate a micro-processing unit, which eliminates recording errors commonly found with reverse-dial indicator and rim-and-face methods. Optical systems automatically maintain the proper orientation and provide accurate offset and angularity data, virtually eliminating operator error. 

Let As be the indicator or recorder error. Then, for small errors... 

Alternative theory 6 (that of motivated recording errors) clearly cannot apply here because Pratt did not know what Pearce s responses were at the time he copied down the order of... 

Appendix 10 shows an example of a sample label. Sample labels may be preprinted to avoid recording errors in the field, particularly for projects with a large number of samples. If filled out by hand in the field, sample labels must be legibly written with non-running ink and secured on the sample containers with clear tape. 

The first and best approach should be to examine the assay procedure that was used to try to find an explanation (e.g., a technical error or even a data recording error) for the outlying value. If a substantial technical error is found, then the outlying value may be discarded, and if possible the assay should be run again to replace it. If no such explanation is found, however, we still may wish to discard grossly aberrant values rather than repeat the entire set of n repetitions of the assay. One approach... 

A critical evaluation of existing elemental data of coal would probably result in identification of anomalous values and elimination of suspect data. Several questions might be answered by such an evaluation for example, do the two K values in the high-ash region of Figure 1 deviate significantly from the trend of the other data because of analytical errors or recording errors ... 

Weathering steel samples were exposed for periods of up to 30 months at nine air monitoring sites in the St. Louis, Missouri area. Climatic and air quality data were recorded during the exposure period and subjected to a rigorous evaluation to eliminate recording errors and to estimate missing values. Weight loss was used as the measure of steel corrosion. 

Alternative models may be developed to include additional covariates which are not measured with error, e.g., X = f(R,Z). The classical model is used when an attempt to measure x is made but cannot be done so due to various measurement errors. An example of this is the measurement of blood pressure. There is only one true blood pressure reading for a subject at a particular point in time, but due to minor calibration errors in the instrument, transient increases in blood pressure due to diet, etc., possible recording errors and reading errors by the nurse, etc., blood pressure is a composite variable that can vary substantially both within and between days. In this case it makes sense to try and model the observed blood pressure using Eq. (2.84). Under this model, the expected value of X is x. In regression calibration problems, the focus is on the distribution of x given X. For purposes herein, the focus will be on the classical error model. The reader is referred to Fuller (1987) and Carroll et al. (1995) for a more complete exposition of the problem. 

One assumption made in any analysis is that the sample collection times are recorded without error. In practice, except for perhaps data obtained from Phase 1, this is rarely the case. In any Phase 3 setting, the probability of data collection errors is high despite the best efforts of sponsors. Sun, Ette, and Ludden (1996) used Monte Carlo simulation to study the impact of recording errors in the sample times on the accuracy and precision of model parameter estimates. Concentration data from 100 subjects were simulated using a 2-com-partment model with intravenous administration having an a-half-life of 0.065 time units and a 3-half-life of 1.0 time units. 

Corrective actions to be taken in cases of malfunctions Detecting and recording errors and implementing corrections Restarting the system and recovering data ... 

Error-free sampling times Sampling times are accurately recorded Error-free covariate values Can reflect inaccuracies in recording covariate information or improper/incorrect transformations... 

All the Mossbauer spectra recorded on Mars have been publically released so that every research group could dispose of them freely. Together with each sampled spectrum, a spectrum of a reference absorber was collected and also the recorded error signal of the driver is provided. As expected, the spectra are not linear in the velocity scale, which causes some calibration difficulties. Agresti et al. [284] calibrated the spectra by considering the a-Fe hnes in the reference target, combined with the error signal of the drive. 

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