Converts Weibull data (failure, suspension, and interval-censored times) into a format suitable for reliability growth analysis (RGA). The function handles exact failure times, right-censored suspensions, and interval-censored data. It approximates interval-censored failures by placing them at the midpoint of the interval. The output is a data frame with cumulative time and failure counts, where the cumulative time is the total time on test of the population: at each event, units that have already failed or been suspended contribute their own time, while units still operating contribute the current event time (their current age). This format can be used with RGA models such as Crow-AMSAA.
Arguments
- failures
A numeric vector of exact failure times. Each failure time indicates when an item failed during the observation period.
- suspensions
A numeric vector of suspension (right-censored) times. A suspension indicates that the item was removed from observation at that time without failure. This parameter is optional and can be NULL if there are no suspensions.
- interval_starts
A numeric vector of interval start times (lower bound of censoring). This parameter is optional and can be NULL if there are no interval-censored data. If provided, it must be the same length as
interval_ends.- interval_ends
A numeric vector of interval end times (upper bound of censoring). This parameter is optional and can be NULL if there are no interval-censored data. If provided, it must be the same length as
interval_starts.
Value
The data frame contains two columns:
- CumulativeTime
Total time on test of the population at each failure event. Failed and suspended units contribute their own time, while units still running contribute the current event time (their current age).
- Failures
Number of failures at each cumulative time point.
The function approximates interval-censored failures by placing them at the midpoint of the interval.
See also
Other data preparation:
sim_failures()
Examples
failures <- c(100, 200, 200, 400)
suspensions <- c(250, 350, 450)
interval_starts <- c(150, 300)
interval_ends <- c(180, 320)
result <- weibull_to_rga(failures, suspensions, interval_starts, interval_ends)
print(result)
#> CumulativeTime Failures
#> 1 900 1
#> 2 1420 1
#> 3 1665 2
#> 6 2155 1
#> 8 2375 1