Data Reduction
17
8
7
6
5
38000
38800
39600
40400
41200
Yield Strength
Figure 1.4 Aluminium casting (A) Problem 1.1 yield data.
Solid Weibull line
~ = 3.12371 + 0.4310 0 = 3,218.959 ± 1,756
7 = 36,497 :i: 1,634 psi
Dotted Gaussian line
/~ = 39,370 psi ~ = 1057 psi.
for 0.025 is 2.069 and x 2 Table E.3 the 0.025 value 38.08 with square root
of 6.1709 and 0.975 value 11.69 with square root value of 3.419.
Using Eq. (1.30)
1057
1057
39,370 - 2.069~- < #t < 39,370 + 2.069
-
-
23
(1.56)
39,275 _< #t -< 39,465
Using Eq. (1.31)
1057~
1057,~-~
6.1709
3.419
839 ~ 6i ~ 1,515psi
(1.57)
The Weibull parameters for 24 data points, N, are Eq.(1.53).
~=B=3.12371
0=3,218.959
V=36,497psi
Convert to infinite sample size with 95% confidence using Eq. (1.37) for