tailieunhanh - MEASURE Evaluation_3

Tham khảo tài liệu 'measure evaluation_3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Simpo PDF Merge and Split Unregistered Version - http tion of the population contained between the smallest and the largest value of a sample of size 10 is 1 . The meaning of the qualification on the average should be properly understood. For any particular sample of size 10 the actual fraction of the population contained in the interval xw - X 1 will generally not be equal to . But if the average of those fractions is taken for many samples of size N it will be close to 1. Tolerance intervals involving confidence coefficients One can formulate more specific questions related to coverages by introducing in addition to the coverage the confidence of the statement about the coverage. For example one can propose to find two order statistics such that the confidence is at least 90 percent that the fraction of the population contained between them the coverage is 95 percent. For a sample of size 200 these turn out to be the third order statistic from the bottom and the third order statistic from the top see Table A30 in Natrella3 . For further discussion of this topic several references are 5 6 Non-normal distributions and tests of normality Reasons for the central role of the normal distribution in statistical theory and practice have been given in the section on the normal distribution. Many situations are encountered in data analysis for which the normal distribution does not apply. Sometimes non-normality is evident from the nature of the problem. Thus in situations in which it is desired to determine whether a product conforms to a given standard one often deals with a simple dichotomy the fraction of the lot that meets the requirements of the standard and the fraction of the lot that does not meet these requirements. The statistical distribution pertinent to such a problem is the binomial see section on the binomial distribution . In other situations there is no a priori reason for non-normality but the data themselves give .