![]() strain fields of unnotched specimens, when interpreted in terms of this intensity factor, show excellent agreement with elastic long crack data. Crack growth results for short cracks in both elastic and plastic. So one has to warn statisticians against using Excel functions for scientific purposes.The “exact” values in the tables were computed by means of SAS for Windows (1996), and they were checked with the program ELV in Knüsel (1989).Ī strain-based intensity factor is introduced which, while becoming equivalent to the linear elastic stress intensity factor for long elastic cracks, admits plasticity by replacing the conventional stress term with a strain term and accounts for the proximity of a short crack to a free surface by the inclusion of a length constant. As to the accuracy a user may expect of a statistical program see Knüsel (1995). ![]() In the view of the author a user of Excel may expect that the computed results are correct with all given digits if Excel prints out a result with nine or ten digits and in fact only one or two of these many digits are correct, then such a result is unacceptable. Furthermore our tables show that the computation of some continuous distributions and their quantiles (Normal, Chi-square, F, t) is unsatisfactory in the tails of the respective distribution. ![]() It is shown that the computation of some discrete distributions (Binomial, Poisson, Hypergeometric) fails even for probabilities in the central range between 0.01 and 0.99 and even for parameter values that cannot be judged as too extreme. ![]() The paper deals with the numerical accuracy of some statistical functions in Microsoft Excel (Excel version in Microsoft Office 97 for Windows).
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