Laboratory operations statistical analysis

Table 35-4 reports ANOVA comparing the METHOD B procedure to the METHOD A procedure for combined laboratories. Thus the combined METHOD B analyses for each sample were compared to the combined METHOD A analyses for the same sample. This statistical test indicates whether there is a significant bias in the reported results for each method, irrespective of operator or location. An apparent trend is indicated using this statistical analysis, that trend being a positive bias for METHOD B as compared to... 

A QA system describes the overall measures that a laboratory uses to ensure the quality of its operation. Typical items include suitable equipment, trained and skilled staff, documented and validated methods, calibration requirements, standards and RMs, traceability, internal QC, PT, nonconformance management, internal audits, and statistical analysis. 

The Technical Services function of AOCS establishes, revises, and annually updates AOCS Methods, the Official Methods and Recommenced Practices of the American Oil Chemists Society22 for fats, oils, and soap technology Spanish AOCS Methods, a Spanish translation of the more commonly used AOCS Methods and Physical and Chemical Characteristics of Oils, Fats and Waxes. Leaders of the methods development committees coordinate closely with AOAC International (formerly the Association of Official Analytical Chemists). AOCS Methods are recognized as Official Methods in US FDA activities and when litigation becomes necessary in industry trade. Additionally, the Technical Services function operates a Laboratory Proficiency Program (formerly the Smalley Check Sample Program) and oversees distribution and statistical analysis of 30 different series of basic laboratory quality assur-ance/quality control test samples. Certification as AOCS Approved Chemists, or as AOCS... 

Neutron activation analysis has proven to be a convenient way of performing the chemical analysis of archaeologically-excavated artifacts and materials. It is fast and does not require tedious laboratory operations. It is multielement, sensitive, and if need be, can be made entirely non-destructive. Neutron activation analysis in its instrumental form, i.e. that involving no chemical separation, is ideally suited to automation and conveniently takes the first step in data flow patterns that are appropriate for many taxonomic and statistical operations. 

In addition to references to specific literature sources, a bibliography is given at the end of the chapter for appropriate statistical textbooks and for ASTM and ISO standards that iipply to quality assurance, statistical analysis, precision, bias and uncertainty, laboratory accreditation, and proficiency testing. The listing of standards is not exhaustiv e only those that are anticipated to be worthwhile for the topic of this chapter are included. These standards, with some exceptions as noted, were developed by committees on statistics and quality as generic standards that apply in principle to all testing and measurement operations. 

The experimental analysis of a real large SOFC generator in operation is a complex task. The generator is a big plant, with many variables which affect its operation therefore, the experimental environment is completely different compared to a laboratory, because it is difficult to control the many variables involved during the development of the experiment moreover, the data acquired in the experimental session have to be carefully analysed, in order to isolate the main effects which have to be detected, to take care of the interactions, and to quantify the significance of every effect. This causes the necessity of a careful design of the experiment coupled with a consequent statistical analysis of the collected data, in order to be able to outline the significance of every observed effect. 

Los Alamos National Laboratory performed separate statistical analyses using the Failure Rate Analysis Code (FRAC) on IPRDS failure data for pumps and valves. The major purpose of the study was to determine which environmental, system, and operating factors adequately explain the variability in the failure data. The results of the pump study are documented in NUREG/CR-3650. The valve study findings are presented in NUREG/CR-4217. 

In the present time with almost unlimited computer facilities in the analytical laboratory, analytical chemists should be able to obtain substantial benefits from the application of time series, information theory, multivariate statistics, a.o. factor analysis and pattern recognition, operations research, numerical analysis, linear algebra, computer science, artificial intelligence, etc. This is in fact what chemo-metricians have been doing for the past decades. 

Sampling is one of the most important operations in a chemical analysis. Chemical analyses use only a small fraction of the available sample. The fractions of the sandy and loam soil samples shown in the photo that are collected for analyses must be representative of the bulk materials. Knowing how much sample to collect and how to further subdivide the collected sample to obtain a laboratory sample is vital in the analytical process. Sampling, standardization, and calibration are the focal points of this chapter. All three steps require a knowledge of statistics. 

XRF analysis is used widely by laboratories that monitor the routine production of materials. In such applications, analyses are required to confirm that the production process is within specified limits. In these (and other) circumstances, it is important to be able to demonstrate that the instrument response has not drifted beyond acceptable limits for day-to-day operation, otherwise the wrong remedial action might be taken, so affecting the quality of the product. Statistical process control procedures require... 

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