exp_prst_plot: Probability Ratio Sequential Test (PRST) Plot

In jjw3952/mcotear: Contains helpful functions for use within MCOTEA

Probability Ratio Sequential Test (PRST) Plot

Description

exp_prst_plot returns parameters defining a PRST for the exponential distribution (as developed by Abraham Wald), and creates the plot of the results and defined parameters.

Usage

exp_prst_plot(
  r = NULL,
  t = NULL,
  mtbf0 = 100,
  mtbfa = 200,
  alpha = 0.1,
  beta = 0.1
)

Arguments

r	(Optional, default as NULL) The cumulative number of failures up to time t. If specified it must be of equal length to t.
t	(Optional, default as NULL) The cumulative (operational) time. If specified it must be of equal length to r.
mtbf0	The minimum acceptable MTBF.
mtbfa	A value of MTBF greater than mtbf0 at which we want to ensure we don't reject the system.
alpha	The producer's risk of rejecting equipment with MTBF > MTBFA (the probility of rejecting good equipment). Default = 0.10.
beta	The consumer's risk of accepting equipment with MTBF < MTBF0. (the probility of accepting bad equipment). Default = 0.10.

Value

The output will return r = the number of failures at which the test terminated, T = the time at which the test is terminated, a = y-intercept for the accept time, b = slope of the accept and reject lines, c = y-intercept of the reject line, df = a data.frame giving the number of failures and the associated time times at which the test is terminated and the equipment accepted or rejected, as well as some text which outputs the form of the accept/reject lines, and the accept/reject times. A plot will also be returned plotting the accept/reject lines, truncation lines, and the observed data as step function if supplied by parameters r and t.

References

Mil-Hdbk-781A

Wald, Abraham. Sequential Analysis. John Wiley & Sons, 1947.

Brazovsky, Igor. Reliability Theory and Practice. Prentice Hall, 1961.

See Also

exp_reliability_req, exp_test_duration, exp_test_demo, exp_prst

Examples

exp_prst_plot(r=NULL, t=NULL, mtbf0=100, mtbfa=200, alpha=.1, beta=.1)
exp_prst_plot(
  r = c(0,1,2,3,4,5,6,6,14),
  t = c(0,100,150,200,250,275,300,1500,2060),
  mtbf0=100, mtbfa=200, alpha=.1, beta=.1)

jjw3952/mcotear documentation built on Sept. 2, 2023, 10:30 a.m.