weibulltools (version 2.0.0)

plot_conf: Add Confidence Region(s) for Quantiles and Probabilities

Description

This function is used to add estimated confidence region(s) to an existing probability plot. Since confidence regions are related to the estimated regression line, the latter is provided as well.

Usage

plot_conf(p_obj, x, ...)
# S3 method for wt_confint
plot_conf(
  p_obj,
  x,
  title_trace_mod = "Fit",
  title_trace_conf = "Confidence Limit",
  ...
)

Value

Returns a plot object containing the probability plot with plotting positions, the estimated regression line and the estimated confidence region(s).

Arguments

p_obj

A plot object returned from plot_prob.

x

Confidence interval as returned by confint_betabinom or confint_fisher.

...

Further arguments passed to or from other methods. Currently not used.

title_trace_mod

A character string which is assigned to the mod trace in the legend.

title_trace_conf

A character string which is assigned to the conf trace in the legend.

References

Meeker, William Q; Escobar, Luis A., Statistical methods for reliability data, New York: Wiley series in probability and statistics, 1998

Examples

# Reliability data:
data <- reliability_data(data = alloy, x = cycles, status = status)

# Probability estimation:
prob_tbl <- estimate_cdf(data, methods = "johnson")

# Example 1 - Probability Plot, Regression Line and Confidence Bounds for Three-Parameter-Weibull:
rr <- rank_regression(prob_tbl, distribution = "weibull3")

conf_betabin <- confint_betabinom(rr)

plot_weibull <- plot_prob(prob_tbl, distribution = "weibull")

plot_conf_beta <- plot_conf(
  p_obj = plot_weibull,
  x = conf_betabin
)

# Example 2 - Probability Plot, Regression Line and Confidence Bounds for Three-Parameter-Lognormal:
rr_ln <- rank_regression(
  prob_tbl,
  distribution = "lognormal3",
  conf_level = 0.9
)

conf_betabin_ln <- confint_betabinom(
  rr_ln,
  bounds = "two_sided",
  conf_level = 0.9,
  direction = "y"
)

plot_lognormal <- plot_prob(prob_tbl, distribution = "lognormal")

plot_conf_beta_ln <- plot_conf(
  p_obj = plot_lognormal,
  x = conf_betabin_ln
)

# Example 3 - Probability Plot, Regression Line and Confidence Bounds for MLE
ml <- ml_estimation(data, distribution = "weibull")

conf_fisher <- confint_fisher(ml)

plot_weibull <- plot_prob(prob_tbl, distribution = "weibull")

plot_conf_fisher_weibull <- plot_conf(
  p_obj = plot_weibull,
  x = conf_fisher
)