View source: R/descriptive_stats.R
prec_rate | R Documentation |
prec_rate
returns the sample size or the precision for the provided
rate.
prec_rate( r, x = NULL, conf.width = NULL, conf.level = 0.95, method = c("score", "vs", "exact", "wald"), ... )
r |
rate or rate ratio. |
x |
number of events. |
conf.width |
precision (the full width of the confidence interval).
Should not exceed 5 times |
conf.level |
confidence level. |
method |
The method to use to calculate precision. Exactly one method may be provided. Methods can be abbreviated. |
... |
other arguments to uniroot (e.g. |
Exactly one of the parameters r
or conf.width
must be passed as NULL,
and that parameter is determined from the other.
The score
, variance stabilizing (vs
), exact
, and
wald
method are implemented to calculate the rate and the precision.
For few events x
(<5), the exact method is recommended.
If more than one method is specified or the method is miss-specified, the 'score' method will be used.
uniroot
is used to solve n for the score and
exact method.
Object of class "presize", a list of arguments (including the computed one) augmented with method and note elements.
Barker, L. (2002) A Comparison of Nine Confidence Intervals for a Poisson Parameter When the Expected Number of Events is ≤ 5, The American Statistician, 56:2, 85-89, doi: 10.1198/000313002317572736
poisson.test
# confidence interval width for a rate of 2.5 events per unit and 20 events, # using the score method prec_rate(2.5, x = 20, met = "score") # number of events to yield a CI width of 2.243 for a rate of 2.5 events per # unit and 20 events, using the score method prec_rate(2.5, conf.width = 2.243, met = "score") # confidence interval width for a rate of 2.5 events per unit and 20 events, # using the exact method prec_rate(2.5, x = 20, met = "exact") # vs and wald have the same conf.width, but different lwr and upr prec_rate(2.5, x = 20, met = "vs") prec_rate(2.5, x = 20, met = "wald")
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