Error constancy

A number of potential sources of error must be taken into account. In the volumetric method the following items need attention (a) constancy of the level of liquid nitrogen (b) depth of immersion of the sample bulb ( S cm) (c) temperature of sample (monitoring with vapour pressure thermometer close to sample bulb) (d) purity of adsorptive (preferably 99-9 per cent) (e) temperature of gas volumes (doser, dead space), controlled to 01 C. 

CU-CUSO4 electrodes with saturated CUSO4 solution are recommended for potential measurements in soil. Their potential constancy is about 5 mV. Larger errors can be traced to chemical changes in the CUSO4 solution. These electrodes have been developed for long-life applications in potential-controlled rectifiers and built-... 

An eluted solute was originally identified from its corrected retention volume which was calculated from its corrected retention time. It follows that the accuracy of the measurement depended on the measurement and constancy of the mobile phase flow rate. To eliminate the errors involved in flow rate measurement, particularly for mobile phases that were compressible, the capacity ratio of a solute (k ) was introduced. The capacity ratio of a solute is defined as the ratio of its distribution coefficient to the phase ratio (a) of the column, where... 

In a previous discussion4 it was pointed out that there is some arbitrariness in the choice of bond energies, arising from uncertainty in the experimental data, lack of constancy of bond energies from compound to compound, and other causes. Because of differences in the data used and their treatment, the values given in that paper and the present one differ somewhat the difference in no case exceeds 0.1 v.e., however, which is of the order of magnitude of the errors inherent in the data. 

Similarly for MF ions D varies between the extremes of 3.5 and 4.2 kK., (72) so that in neither case is any sensible error involved in assuming constancy. However, the determination of D and the assignment of the Laporte-allowed charge-transfer bands also permits the evaluation of Jorgensen s (91) optical electronegativity parameters. These are obtained using the relationship... 

Theory for the transformation of the dependent variable has been presented (Bll) and applied to reaction rate models (K4, K10, M8). In transforming the dependent variable of a model, we wish to obtain more perfectly (a) linearity of the model (b) constancy of error variance, (c) normality of error distribution and (d) independence of the observations to the extent that all are simultaneously possible. This transformation will also allow a simpler and more precise data analysis than would otherwise be possible. 

The dependence of precision on different parameters has already been discussed. Precision is strongly dependent on the constancy of migration data. Thus, the stability of the EOF is most important. Buffer recipes describe clearly the preparation and avoid errors caused by, e.g., a poorly calibrated pH electrode. 

On the other hand, its should be emphasized that such basic analytical properties as precision, sensitivity and selectivity are influenced by the kinetic connotations of the sensor. Measurement repeatability and reproducibility depend largely on constancy of the hydrodynamic properties of the continuous system used and on whether or not the chemical and separation processes involved reach complete equilibrium (otherwise, measurements made under unstable conditions may result in substantial errors). Reaction rate measurements boost selectivity as they provide differential (incremental) rather than absolute values, so any interferences from the sample matrix are considerably reduced. Because flow-through sensors enable simultaneous concentration and detection, they can be used to develop kinetic methodologies based on the slope of the initial portion of the transient signal, thereby indirectly increasing the sensitivity without the need for the large sample volumes typically used by classical preconcentration methods. 

Table II shows effects of the disorder parameter on the calculated crystallinity of cotton, nylon 66 (PA 66) and PET fiber samples. When k = 0, no correction for distortion is made during calculation of crystallinity. Accordingly, values of X become smaller as the integration intervals increase. On the nomogram of K values, it is possible to determine the disorder parameter value that maintains as approximately constant this crystallinity when using the different intervals the deviation from the constancy is used, in the computing program to determine the best value of k and to estimate the errors of these analyses. The disorder parameter k is higher in cotton and PA 66 than in all PET fibers. Besides, one can see that apparent crystallinity values (disorder parameter not considered) are lower than the true ones.

Cardei and Funt (1999) suggested to combine the output from multiple color constancy algorithms that estimate the chromaticity of the illuminant. Their approach is called committee-based color constancy. By combining multiple estimates into one, the root mean squared error between the estimated chromaticity and the actual chromaticity is reduced. Cardei and Funt experimented with committees formed using the gray world assumption,... 

The potentiometer employed was a low-resistance Type K instrument by Leeds and Northrup, with which was used a suspended coil galvanometer by the same makers. The latter was adjusted by means of a shunt until its vibrations were aperiodic, and had under these conditions a sensibility more than adequate. Care was taken before the beginning of an experiment to bring the potentiometer battery to such constancy of e. m. f. that errors from this source were negligible, and this constancy was checked at least once in the course of each series of observations by comparisons with a set of standard cells. 

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