qq.expo.weibull: Quantile versus quantile (QQ) plot for the Exponentiated Weibull(EW) distribution

Description

The function qq.expo.weibull() produces a QQ plot for the Exponentiated Weibull(EW) based on their MLE or any other estimate. Also, a line going through the first and the third quartile can be sketched.

Usage

qq.expo.weibull(x, alpha.est, theta.est, main = " ", line.qt = FALSE, ...)

Value

The function qq.expo.weibull() carries out a QQ plot for the Exponentiated Weibull(EW).

Arguments

x: vector of observations
alpha.est: estimate of the parameter alpha
theta.est: estimate of the parameter theta
main: the title for the plot
line.qt: logical; if TRUE, a line going by the first and third quartile is sketched.
...: additional arguments to be passed to the underlying plot function.

References

Mudholkar, G.S. and Srivastava, D.K. (1993). Exponentiated Weibull family for analyzing bathtub failure-rate data, IEEE Transactions on Reliability, 42(2), 299-302.

Murthy, D.N.P., Xie, M. and Jiang, R. (2003). Weibull Models, Wiley, New York.

Nassar, M.M., and Eissa, F. H. (2003). On the Exponentiated Weibull Distribution, Communications in Statistics - Theory and Methods, 32(7), 1317-1336.

Examples

Run this code

## Load data sets
data(stress)
## Maximum Likelihood(ML) Estimates of alpha & theta for the data(stress)
## Estimates of alpha & theta using 'maxLik' package
## alpha.est =1.026465, theta.est = 7.824943

qq.expo.weibull(stress, 1.026465, 7.824943, main = " ", line.qt = FALSE)