Package 'rSSP'

Title: Single Acceptance Sampling Plans for Time-Truncated Life Test
Description: Designing single acceptance sampling inspection plans under time-truncated life tests and calculates the minimum required sample size subject to a consumer's risk constraint on the probability of acceptance. Failure probabilities can be supplied from any lifetime distribution, allowing the methodology to be applied without restricting the analysis to a particular probability model. The package also provides plot of the required sample size against the termination ratio. Tripathi et al. (2023) <doi:10.1007/s41872-023-00221-x>; Hu and Gui (2018) <doi:10.1080/09720510.2017.1413044>.
Authors: Harsh Tripathi [aut, cre]
Maintainer: Harsh Tripathi <[email protected]>
License: GPL-3
Version: 0.1.0
Built: 2026-09-15 10:02:35 UTC
Source: https://github.com/cran/rSSP

Help Index


Plot Sample Size Against Termination Ratio

Description

Calculates the minimum sample size for different termination ratios and plots the resulting sample size against the termination ratio.

Usage

plot_single_asip(p, a, b = 1, be = 0.25, c = 0, ylim = c(0, 50))

Arguments

p

User-defined probability of failure corresponding to each termination ratio.

a

Numeric vector of termination ratios.

b

Quality ratio. It may be a single value or a vector having the same length as a.

be

Producer's risk.

c

Acceptance number.

ylim

Numeric vector of length two specifying the limits of the y-axis. Default is c(0, 50).

Details

The user supplies the corresponding values of p calculated from their own lifetime distribution.

Value

A data frame containing a, b, p and the required sample size n.

Examples

# Example 1: User-defined failure probabilities
p <- c(0.05, 0.10, 0.15, 0.20)

plot_single_asip(
  p = p,
  a = c(0.5, 1, 1.5, 2),
  b = 1,
  be = 0.25,
  c = 0,
  ylim=c(0,50)
)

# Example 2: Failure probabilities obtained from
# a Burr Type X lifetime distribution

al <- 0.5
b <- 1
a <- c(0.4, 0.6, 0.8, 1, 1.5, 2, 2.5, 3)

h <- sqrt(
  -log(
    1 - (1/2)^(1/al)
  )
)

p <- (1 - exp(-(a * h / b)^2))^al

plot_single_asip(
  p = p,
  a = a,
  b = b,
  be = 0.25,
  c = 6,
  ylim = c(0, 50)
)

Single Acceptance Sampling Inspection Plan

Description

Calculates the minimum required sample size for a single acceptance sampling inspection plan under a time-truncated life test using the producer's risk condition Pa <= be.

Usage

single_asip(p, a, b, be = 0.25, c = 0)

Arguments

p

User-defined probability of failure before the termination time. It must lie between 0 and 1.

a

Termination ratio, defined as a = t/theta0. It must be a positive numeric value.

b

Quality ratio, defined as b = theta/theta0. It must be a positive numeric value.

be

Producer's risk. It must be a value between 0 and 1.

c

Acceptance number. It must be a non-negative integer.

Details

The probability p is user-defined. Therefore, no particular lifetime distribution is embedded in this function.

Value

A data frame containing a, b, p, be, c, required sample size n, and probability of acceptance Pa.

Examples

# Example 1: User-defined failure probabilities
p <- c(0.05, 0.10, 0.15, 0.20)

single_asip(
  p = p,
  a = c(0.5, 1, 1.5, 2),
  b = 1,
  be = 0.25,
  c = 0
)

# Example 2: Failure probabilities obtained from
# a Burr Type X lifetime distribution

al <- 0.5
b <- 1
a <- c(0.4, 0.6, 0.8, 1, 1.5, 2, 2.5, 3)

h <- sqrt(
  -log(
    1 - (1/2)^(1/al)
  )
)

p <- (1 - exp(-(a * h / b)^2))^al

single_asip(
  p = p,
  a = a,
  b = b,
  be = 0.25,
  c = 6
)