Copy/paste
data col
- or -
Drag/drop
text file
- onto -
textarea
Number of suspended
data(NOT included):
Use lower tail data?
Check box for yes.
nc +ns =n

Weibull LS ML
Scale η
Shape α
MSE Σd2/nc
mean
CV
5%tile R05
Ω(R05|75%)
2-parameter Weibull CDF(x) = 1 - e-(x/η)α

LS uses the method of Least Squares to estimate the 2 parameters of a Weibull distribution of a complete data set or low tail fit. Resistance is regressed on median rank.
See ASTM D5457 Section X2, (X2.5), (X2.6)

ML uses the method of Maximum Likelihood to estimate the 2 parameters of a Weibull distribution of a complete data set or low tail fit.
See ASTM D5457 Section X2, (X2.2), (X2.3)

Parameter estimation for lower tail data require minimum failed observations. For sample sizes of n = 600 or less, 60 = nc with the suspended value rs = r[60]. For sample sizes of 600 < n,
(0.1 • n) = nc with the suspended value rs = r[0.1 • n].
See ASTM D5457 Sections A1.2.2, X2

MSE Σd2/nc is the Mean Squared Error. MSE measures the average of the squares of the errors; that is, the difference between the estimated resistance and observed data.

Ω(R05|75%) is a data confidence factor on R05, the fifth percentile, with 75% confidence. See ASTM D5457 Section A1.5

Copy/paste data column or drag/drop text file onto the textarea. Pro-
gram parses, ranks, analyzes, & graphs (Google Charts API) the data.

Wgraph.html developed by Joe Murphy, 25 February 2018, using FireFox ESR 52.6.0 (32-bit). Wgraph.html freely available for personal use.