Breaking stress (in GPa) of 100 carbon fibre specimens. This dataset exhibits a unimodal (increasing-then-decreasing) hazard pattern that classical distributions like the Weibull cannot adequately capture.
Format
A data frame with 100 rows and 2 columns:
- time
Breaking stress in GPa
- status
Event indicator (1 = event occurred)
Source
Nichols, M. D., & Padgett, W. J. (2006). A bootstrap control chart for Weibull percentiles. Quality and Reliability Engineering International, 22(2), 141-151.
Examples
data(carbon_fibres)
# \donttest{
fit <- fit_betadanish(survival::Surv(time, status) ~ 1, data = carbon_fibres)
#> Warning: The times look recorded on a grid of 0.01. The point-density likelihood treats them as exact, which understates the standard errors. Consider grouped = TRUE.
#> Warning: b-hat is only 0.55 standard errors from 1, close to the b = 1 non-identifiability ridge. Consider the ED submodel (submodel = TRUE). See the Identifiability section of ?fit_betadanish.
#> Warning: The fitted correlation between a-hat and c-hat is -0.953, so effectively only the product c*a is identified. Individual estimates of a and c should not be interpreted.
#> Warning: 2 starting point(s) reached a degenerate ridge and were discarded. The reported fit is the best admissible optimum. If this is most of the grid, the four-parameter model is a poor choice for these data.
# }