Mean error

Sample 1 Sample 2 Average Mean error Spontaneous reaction... 

When finger agnosia was present, there were more errors with the nonpreferred hand (2.05 mean errors) than with the preferred hand (1.88 mean errors). Fewer than 10 percent of the sample showed performances on the hand dynamometer below the normative standards. Conversely, nearly 50 percent of the sample showed below normal performances on the finger oscillation test, a finding that suggests that fine motor dysfunction is more prevalent as a result of PCP and other drug abuse than gross motor dysfunction. 

The sample has been cleaned of 5 suspected binaries and of 6 stars with a 215globular cluster NGC6528 [2]. The final sample contains 217 stars. The RV distribution is shown in Figure 1. The associated errors are smaller than 0.45 km.s-1, with a mean error value of 150 m.s-1. 

Based on previous recommendations [31], a combination of graphical techniques and error index statistics was used for evaluating the goodness-of-fit between the simulated and observed streamflow values, both during the calibration and validation period. The used statistics were the mean error (ME), the percent bias (PBIAS, [32]) and the Nash-Sutcliffe efficiency (NSeff, [33]) ... 

For the G2 set of compounds (a standardized test set of small molecules) the mean error to the atomization energy is approximately 2.5 kcal mol-1 at the B3LYP level, compared with 78 kcal -mol-1 for HF theory, and in the range of lkcalmor1 for the most accurate correlated ah initio methods. For most cases in which a moderately sized systems (10-50 atoms) is to be investigated, the B3LYP functional is currently the method of choice. 

Points Are Means - Error Bars Are + One Standard Deviation) FIGURE 22.6. Variance inflation. 

A large number of tests showed that a value of 0.25 for s was optimal. The mean error in the dissociation energies for 49 diatomic molecules was reduced from 0.2 eV to 0.1 eV. Using an average s was particularly impressive for triply bonded molecules The average error for N2, P2, and As2 was reduced from 0.45 eV to less than 0.15 eV. Similar absolute improvements were obtained for excitation and ionization energies.20... 

There is no consistent trend with fraction neutralization, so the correlating equation is adequate. However, series 3 is high and series 8 is low, suggesting systematic errors. Each of series 2 through 8 are internally consistent, with standard deviations around a mean error less than 17%. 

Series 8 in combination with earlier series was intended to provide data on the effects of total anion concentration. The results are internally consistant with the correlation, having a standard deviation of about 15% around the mean error. However the measured values of PSO2 were about 40% lower than the general correlation. An SO2 analyzer, rather than iodine titration, was used to determine SO2 gas concentration from the saturator. The analyzer was calibrated with dry SO2/N2 span gas. In later experiments it was shown that humid gas gives a lower analyzer response. With constant fraction neutralization increased anionic concentration increases PSO2 because pH decreases faster than effective bisulfite activity. 

Table 1.12 Statistical measures of errors for extrapolated CCSD(T) AEs relative to experiment (kJ/mol). A is the mean error, Astd is the standard deviation around the mean error, Aabs is the mean absolute error, and Amax is the maximum absolute error.

Unfortunately, definitions, nomenclature, and abbreviations used for performance criteria are sometimes confusing (Frank and Todeschini 1994 Kramer 1998). For instance in the abbreviations MSEC, PRESS, RMSEP, SEC, SEE, SEP, E means error or estimate, R means residual or root, and S means squared or standard or sum. To make it not too complicated, at least in these examples, C is always calibration, M is mean, and P is prediction. 

Compared with the X-ray model, 110 atoms differ by less than 0.31 A (mean error 0.14 A), 90 of those atoms differ by less than 0.20 A (mean error 0.12 A). 5 atoms differ between 0.31 - 0.85 A (mean error 0.59A). There are 14 atoms which differ from the X-ray model by more than 1.2 A,... 

Second period diatomics are excellent representative systems for assesing the suitability of methods that are under development. A large number of vertical excitation energies are available. The size of these molecules may be small but the physical contents of the states can be very diverse. The condition required for extrapolating the mean errors to greater systems is the size-extensivity of the... 

Concerning the VEE, we have chosen, as standard references for comparison, the EOM-CCSD results from Stanton et al. [56] and from Comeau and Bartlett [57]. Results from other very efficient state-of-the-art methods such as Exponentially Generated Cl or the now widely used CASPT2 could also have been used. In general, these are methods from which mean errors in VEE less than 0.2 eV might be expected provided that the basis set used is at least of split-valence plus polarization quality and it is augmented in a well-conditioned way to account for Rydberg states. 

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