trend_test | R Documentation |
trend_test
tests to distinguish
between "no trend" and trends in Poisson Processes.
a trend following the Nonhomogeneous.
Laplace Centroid Test: Optimal for distinguishing between "no trend"
and a trend following the Nonhomogeneous Poisson Process (NHPP)
Exponential Law model.
Military Handbook Test: From Mil-HDBK-189, is optimal for
distinguishing between "no trend" and a trend following
the NHPP Power Law or Duane model.
See:
NIST Trend Tests
trend_test(t, T, fail.trunc = TRUE)
t |
A list of failure time vectors. Each vector should indicate a different system, i.e. if you have multiple systems each systems' failure times should be in it's own vector. |
T |
A list of Total Time on Test (TTT) (i.e. test duration) vectors. The vectors in the list should be of length 1, and each vector should indicate a different system, i.e. if you have multiple systems each systems' TTT should be in it's own vector. |
fail.trunc |
Logical indicating if the test was failure terminated. |
The output will be a list identifying the tests, test statistics, degrees of freedom (where applicable), and p-values.
power_law_process
, power_law_mcf
,
mcf
, ttt
, common_beta
data(amsaa)
# Three systems all time truncated at 200 hours
trend_test(
t = split(amsaa$Time, amsaa$System),
T = list(200,200,200),
fail.trunc = FALSE)
# Three systems all failure truncated
trend_test(
t = split(amsaa$Time, amsaa$System),
T = list(197.2,190.8,195.8),
fail.trunc = TRUE)
# One system, time truncated
trend_test(
t = list(subset(amsaa$Time, amsaa$System == "S1")),
T = list(200),
fail.trunc = FALSE)
# One system, failure truncated
trend_test(
t = list(subset(amsaa$Time, amsaa$System == "S1")),
T = list(197.2),
fail.trunc = TRUE)
rm(list = c("amsaa"))
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