Calculation and expression of results

Probabilistic analysis Calculations and expression of health risks using multiple-risk descriptors to provide the likelihood of various risk levels. Probabilistic risk results approximate a full range of possible ontcomes and the likelihood of each, which is often presented as a freqnency distribntion graph, thns allowing uncertainty or variability to be expressed quantitatively (USEPA, 1999). 

Check the rules for significant figures as needed and determine which rules apply. Carry out the calculation and express the result in the correct number of significant figures. 

Perform the following calculations and express the results in the correct units and number of significant figures. 

Perform the following calculations, and express the results in the correct units and with the proper number of significant figures. Note, in problems with multiple steps, it is better to perform the entire calculation and then round to significant figures. 

A chemical analysis is only as good as the numbers that go into calculating and expressing the result. Therefore, data analysis is a crucial aspect of chemical analysis. All analytical measurements are subject to greater or lesser degrees of error. So every reasonable effort is made to reduce the amount of error in an analytical measurement. Since some error is inevitable, it is important to know the degree of error and express it correctly in the final result. 

In doing analytical calculations and expressing analytical results, it is important to know and correctly handle and express the uncertainties of the numbers used. For example, a skilled analyst can read the volume delivered by a laboratory burette to the nearest 0.01 mL. Therefore, a volume expressed as 36.27 mL implies that the volume is within 0.01 mL of 36.27 mL and has an uncertainty of 0.01 mL. It would be incorrect to express the volume as 36.270 mL because it is not known to the nearest 0.001 mL as that number would imply. It would also be incorrect to express the volume as 36.3 mL because the value is known more accurately than 0.1 mL. 

In doing analytical calculations and expressing analytical results, it is important to know and correctly handle and express the uncertainties of the numbers used, a... 

PRACTICE EXAMPLE A Perform the following calculation, and express the result with the appropriate number of significant figures. 

Note that for the calculations of precision and standard deviation (equations 38-1 through 38-4), the numerator expression is given as 2(n — 1). This expression is used due to the 2 times error contribution from independent errors found in each independent set (i.e., X and Y) of results. 

Methods involving quantitation of conjugated azopigment directly measure the number of groups transferred and thus, by calculation, GTR. Expression of the results in function of bilirubin equivalents conjugated is equivocal. 

More complicated anisotropies of the potential are, for example, encountered in the association of two linear dipoles. Adiabatic channel potential curves for this case have been calculated and expressed analytically in Ref. 16. More systematic studies, also comparing SACM and trajectory results, were reported in Ref. [36], One may as well consider open-shell effects for example, the association of two open-shell HO radicals in their lowest rotational state was treated in Ref. 37. Figure 12 shows the lowest rovi-bronic adiabatic channel potential curves for this system. The ultimate goal... 

Column test (described in Dutch standard NEN 7343) is intended to simulate the percolation of (acidic) rainwater through granular materials in a road construction or landfill. The material is placed in a column with a diameter of 5 cm and height of 20 cm, and acidified demineralized water is then passed upwards through it. The eluate is collected in seven fractions at a liquid/solid ratio of between 0.1 and 101 kg-1. The leaching is calculated and expressed in mg kg 1 as a function of time, based on the analysis results. 

Davies [33] analyzed the published data and expressed the result in the form of Re as a function of C Re that is suitable for calculating the velocity when the diameter is known. 

Among a number of procedures that were proposed for quantitative determinations, only some which make use of the measurements of a variable and its comparison to a calibration curve will be considered. The results of all but one of the procedures below are expressed in arbitrary units the concentration of the antigen in a solution chosen as standard. The concentration determined may be corrected by calculation and expressed in weight of antigen per unit volume if such a concentration in the standard solution is known. 

A granite rock sample contains 6 yug/g (ppm) total U. Assuming that all daughters in the decay series are in secular equilibrium in this sample, calculate the concentrations of - 11, U, and Ra, and express the results in terms of Bq/g and pCi/g. Speculate on the mineralogic location of the U in the rock and the geologic and hydrogeologic history of the sample. 

Transfection and expression of the GFP protein decreased exponentially in irradiated samples, but at a slower rate than the loss of supercoiled forms. This resulted in a target size considerably smaller than the size of the DNA molecule, only about one-third the mass. The map of this plasmid (Fig. 4) shows that the segment of the plasmid directly involved in transfection activity (which includes the CMV promoter, GFP gene, SV40 intron and polyadenylation signal) has a calculated mass of 1067.880 kDa. 

Calculate the cation exchange capacity of tire mineral in Problem 12 and express the result in millimoles(+) per kilogram. Compare this value to the value normally given for montmorillonite. 

The method use to normalize and express data should be decided preferably no later than at the end of the feasibility studies. Comparisons of results from day to day and among laboratories are most accurate when done using normalized data. For example, in ELISA systems, optical density (OD) values are absolute measurements that are influenced by ambient temperatures, test parameters, and photometric instrumentation. Therefore, results need to be calculated and expressed as a function of the reactivity of one or more serum control samples that are included in each run of the assay. 

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