Comparing Test Results

Procedure for conditioning test specimens can call for the following periods in a standard laboratory atmosphere [50 2% relative humidity, 73.4 1.8°F (23 1°C) Adequate air circulation around all specimens must be provided. The reason for this test is due to the fact the temperature and moisture content of plastics affects different properties such as the physical and electrical properties. In order to get comparable test results at different times and in different laboratories a standard has been established. 

The accuracy of an analytical method is given by the extent by which the value obtained deviates from the true value. One estimation of the accuracy of a method entails analyzing a sample with known concentration and then comparing the results between the measured and the true value. The second approach is to compare test results obtained from the new method to the results obtained from an existing method known to be accurate. Other approaches are based on determinations of the per cent recovery of known analyte spiked into blank matrices or products (i.e., the standard addition method). For samples spiked into blank matrices, it is recommended to prepare the sample at five different concentration levels, ranging over 80-120%, or 75-125%, of the target concentration. These preparations used for accuracy studies usually called synthetic mixtures or laboratory-made preparations . 

Therefore, let us start by proposing a definition, one that can at least serve as a basis for our own discussions. Let us define linearity as The property of data comparing test results to actual concentrations, such that a straight line provides as good a fit (using the least-squares criterion) as any other mathematical function. ... 

Limitations in Analytical Accuracy Part 3 - Comparing Test Results for Analytical Uncertainty... 

The selectivity of an analytical method is determined by comparing test results from the analysis of samples containing impurities (related compound), degradation products (originated from samples submitted to stress conditions), or placebo ingredients with those obtained from the analysis of samples without impurities, degradation product, or placebo ingredients. 

Initial current, voltage, luminance, color coordinate properties, and luminance degradation properties were evaluated for the step 5 product and a styryl comparative. Testing results are provided in Table 1. 

Accuracy can be assessed in several ways. Since for real samples the true value is not known, one approach is to compare test results from the method with results from an existing, alternative, well-characterized method, the accuracy of... 

Compare test results with master data. Again, this can be done automatically if such software is built into the system. 

Accuracy criteria are not applicable to toxicity testing endpoints, because there are no standard organism responses against which to compare test results. In place of... 

Preparation of Test Samples. Almost all properties of coatings depend on the layer thickness of the film. To obtain reproducible comparable test results, measurements must be made on carefully prepared films with a defined layer thickness. Films may be either free or applied to a substrate. In some cases film properties are also measured on films with different thicknesses. 

TCBF and Mixed TCBF Copolymers. Polymers in-corporating TCBF at both levels as well as the mixed TCBF copolymers proved to be superior to bisphenol A homopolymer in practically every respect studied. Comparative testing results are presented in TeUsle III. 

COMPARATIVE TESTING RESULTS OF TCBF, TCBF-0, AMD MIXED TCBF MODIFIED COPOLYCARBONATES VERSUS BA AND TCBA POLYCARBONATES... 

The following pages describe selected statistical methods suitable for tackling individual problems arising from routine analysis with the aim of being able to evaluate and compare test results. 

The detection limit is the smallest amount of analyte that can be detected but not necessarily quantitated as an exact value in a sample. For instrumental methods, the investigator may compare test results from blanks and samples of increasingly low concentrations and establish at which concentration the analyte signal is distinguishable above the noise. Usually a signal-to-noise ratio of 2 1 or 3 1 is acceptable. 

Ensure comparison of like with like when comparing test results... 

Comparing test results with the goals and objectives of the test is the clearest measure of the success of the test. In this way, opportunities to improve the test by revising its design, exploiting scientific and technological advances, and considering new or additional information can be achieved. 

The results obtained from tests can vary considerably. This may be due to many factors, such as differences in the shape or size of the test piece or perhaps its preparation. The storage of the material, test method or conditions can all make substantial differences to test results. Polymer behaviour is particularly sensitive to the preconditioning of the test piece and the actual test conditions. Comparable test results can never be obtained unless care is taken to ensure uniform temperature, humidity le.vels and testing rates. To ensure reproducible results that can be directly compared to results from other laboratories, standardised equipment design and test procedures must be used. Standards also help in indicating suitable test conditions and techniques as well as revealing possible sources of test error. 

The number of efficiency indicates the average numerical progress per computed gradient for a given problem. Thus it allows to compare test results obtained by different numerical procedures for a given problem. But the question whether a procedure works better than another one cannot generally be settled by it. 

Corrosion testing methods are like systems of units comparable testing results from different laboratories can be obtained only on the basis of common, standardised testing methods. The first systematic tests of atmospheric corrosion of steel were launched in the United States by ASTM [11]. 

In the early years of the SPT, equipment and procedural differences made it impossible to compare test results. However, the procedures described in ASTM D1583 and recommendations summarized by Seed et al. (1985) have largely standardized the test, hence its name. The test requires the 140 lb hammer to be raised 30 in. and dropped, driving the sampler into the soil. This process is repeated until the sampler has penetrated 18 in. into the soil at the bottom of the borehole. The number of blows required to advance the sampler each of three 6 in. increments are recorded. After lifting the split-spoon sampler from the borehole and removing the soil... 

Reproducibihty Comparing test results between different laboratories using the same sample and materials. 

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