Judgement sampling

The data within each of the two samples should be drawn from populations that are normally distributed and have equal SDs. We have to be aware that the data we are dealing with are small samples. Judgements can be tricky. Even if populations adhere perfectly to the above requirements, small samples drawn from them are unlikely to have perfect, classic, bell-shaped distributions or to have exactly coincident SDs. 

Table 4 Northview Sample Judgements on Appropriate Punishments for the Mods and Rockers...

Taste and Odor. The measurement of taste and odor is somewhat subjective and depends on the personal judgements of individuals. Panels of not less than five observers, and preferably more than ten, are used. The sample is diluted with odor-free water until a ratio at which the odor is just perceptible is determined this ratio is called the threshold odor number (TON). A similar method is used to detect a distinct taste in water (see Flavor characterization). ... 

The aims of sampling are to establish whether eontaminants are present, their distribution and eoneentrations. Commonly-used sampling regimes inelude square grid, stratified random or simple random teehniques. Evenly-spaeed sampling points may be appropriate if the eontamination is visible otherwise judgement is required based on whether the land slopes or is flat. Samples are also taken near to the point of release. 

It is advantageous to attach the micropipet to a sampler diluter. In this manner, the sample is aspirated by means of a plunger. The technician is not required to adjust the volume nor to make a judgement, because this is being done by a plunger, and accuracy is a function of the sampler diluter. If then one wipes off the tip and then ejects a diluting fluid, one could then proceed to measure out very small samples limited only on the nature of the tip. This can be seen in the sequence of events in Figure 7. 

The mural paintings in the Monumental Cemetery of Pisa were detached in a restoration after the Second World War, and were later restored on several occasions. They showed an advanced state of degradation. In Figure 11.10 the pyrograms of two samples collected from the paint surfaces (CSG 13bis from Universal Judgement and CSA 5b from Stories of Holy Fathers ) are compared with the pyrograms of nitrocellulose, starch and arabic gum. 

Figure 11.10 Comparison of extracted ion pyrograms of fragment ion m/z 217 of two samples collected from the paint surfaces of Universal Judgement and Stories of Holy Fathers (Monumental Cemetery of Pisa, Italy, painted by Buffalmacco, fourteenth century) with nitro cellulose, starch and arabic gum. 1, Unidentified compound 2, 1,2,3,5 tetrakis (O TMS) xylo furanose 3, tri (O TMS) levoglucosane 4, isomer of 1,2,3,5 tetrakis (O TMS) xylofuranose. Pyrogram obtained with a resistively heated filament at 60CPC in the presence of HMDS [30]...

The sample was collected from a decorative frame of the Universal Judgement and, as in Case Study 2, was detached during restoration. It had a completely waterproof surface, due to materials used in a past restoration treatment, preventing any further intervention. In the same sample several organic materials were identified (Figure 11.11) ... 

Figure 11.11 Pyrogram of a paint sample collected from a decorative frame of the Universal Judgement by Bonamico Buffalmacco (fourteenth century, Monumental Cemetery of Pisa, Italy). Pyrolysis was performed with a microfurnace pyrolyser, at 600°C, in the presence of HMDS. 1, Benzene 2, ethyl acrylate 3, methyl methacrylate 4, acetic acid, trimethyl silyl ester 5, pyrrole 6, toluene 7, 2 methylpyrrole 8, 3 methylpyrrole 9, crotonic acid 10, ben zaldehyde 11, phenol 12, 2 methylphenol 13, 4 methylphenol 14, 2,4 dimethyl phenol 15, benzyl nitrile 16, 3 phenylpropionitrile 17, indole 18, phthalate 19, phthalate 20, ben zyl benzoate HMDS pyrolysis products [27]...

Judgement sampling involves using knowledge about the material to be sampled, and the reason for sampling, to select specific samples. 

In conclusion, the sequential U test is useful for the judgement of identity between MWDs of a pair of polymer samples whose molecular weight averages are Identical within the experimental errors. Identity of MWDs of the two polymer samples was established with more than four pairs of parallel measurements, and the disagreement of MWDs with two to four pairs of parallel measurements. Though this statistical treatment is useful for the identification or differentiation of the MWDs of the pair of polymers, it can not detect small differences in shapes of the both chromatograms. 

In order to understand the behavior of the soil-like aerosols, samples of exposed surface soils were collected in the vicinity of each of the sites. Additional samples were obtained from locations in the Ute Indian area, for a total of 110 soil samples. The samples were collected by first selecting a location representative of the surrounding area. Factors considered at each site Included ground cover, agricultural practices, and a judgement of the ability of the surface to be resuspended. An area approximately 15 cm square was removed to a depth of 2-3 cm and transported to Davis in a plastic zip-lock bag or a nalgene bottle. 

Statistic a value calculated from a sample of observations and used to make some judgement about the observations. Sometimes used to estimate a parameter of a distribution. 

Compare the odor of the numbered samples with that of the reference sample "S." Indicate the degree of difference, if any, from the odor of "S" by checking the appropriate box opposite the term which best describes the degree of odor difference. Take as much time as you need. Base vour judgement on odor quality and not intensity. 

Experimental data obtained by any of the assay methods must be evaluated by someone. Judgements are commonly based on the experience of the analyst and accumulated laboratory data or published results. The evaluations range from comparison with a simultaneous standard to highly sophisticated statistical equations requiring many calculations. Evaluation of juice content should be considered as an estimate in the context of placing the sample somewhere in the natural population distribution, and the probability of that estimate should be reported. Unfortunately, many literature reports fail to mention or minimize the uncertainty of the estimate. In samples where the presence of foreign substances is proven, one can state with absolute certainty that the juice has been adulterated. 

Determination of differences in results Sound scientific judgement, well thought out experiments and previous experience with the drug substance or product must be used to determine if an observed difference in degradation rates between samples is due to an actual difference in stability properties or whether the difference is within experimental error. Checking several containers of the same sample under the stress conditions can be used to establish the reproducibility of the observed degradation rate. This would include variability due to the individual samples and the... 

An aspect of matrix RMs which is of considerable importance is the question of commutability or horizontal traceability. This refers to the scope of the materials, i.e. the extent to which a matrix RM of a particular composition may reliably be used to evaluate a measurement procedure that is applied to a routine test sample of a different composition. The differences in composition between a reference matrix and a routine test sample matrix must not cause the two materials to behave differently when a particular analytical method is applied. At present, the extent to which this is true is largely a matter of expert judgement based on knowledge of the measurement application. A better and more systematic understanding of the factors affecting horizontal traceability will enable users to select appropriate matrix RMs more reliably and producers to target their production activities more efficiently. 

Data are not random but are representative in other ways. This may mean, for example, that the data are a stratified sample applicable to the real-world situation for the assessment scenario of interest. In this case, frequentist methods can be used to make inferences for the strata that are represented by the data (e.g. particular exposed subpopulations), but not necessarily for all aspects of the scenario. However, for the components of the scenario for which the data cannot be applied, there is a lack of representative data. For example, if the available data represent one subpopulation, but not another, frequentist methods can be applied to make inferences about the former, but could lead to biased estimation of the latter. Bias correction methods, such as comparison with benchmarks, use of surrogate (analogous) data or more formal application of expert judgement, may be required for the latter. 

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