A spring maker is supplying helical coil springs meeting the requirement for a spring rate k of 10 ± 1 lbf/in. The test program of the spring maker shows that the distribution of spring rate is well approximated by a normal distribution. The experience with inspection has shown that 8.1 percent are scrapped with k < 9 and 5.5 percent are scrapped with k > 11. Estimate the probability density function.
Answer to relevant QuestionsThe lives of parts are often expressed as the number of cycles of operation that a specified percentage of a population will exceed before experiencing failure. The symbol L is used to designate this definition of life. Thus ...For Prob. 20–3, plot the histogram with f / (Nw) as ordinate and superpose a normal distribution probability density function on the histographic plot.The tensile 0.2 percent offset yield strength of AISI 1137 cold-drawn steel rounds up to 1 inch in diameter from 2 mills and 25 heats is reported histographically as follows: Where Sy is the class midpoint in kpsi and f ...A cold-drawn 301SS stainless steel has an ultimate tensile strength given by Sut = W [151.9, 193.6, 8.00] kpsi. Find the mean and standard deviation.A 35018 malleable iron has a 0.2 percent offset yield strength given by the Weibull distribution Sy = W [34.7, 39.0, 2.93] kpsi. What are the mean, the standard deviation, and the coefficient of variation?
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