Functions to convert pi, lambda and median values into each other.
getLambdaByPi(piValue, eventTime = 12L, kappa = 1)getLambdaByMedian(median, kappa = 1)
getHazardRatioByPi(pi1, pi2, eventTime = 12L, kappa = 1)
getPiByLambda(lambda, eventTime = 12L, kappa = 1)
getPiByMedian(median, eventTime = 12L, kappa = 1)
getMedianByLambda(lambda, kappa = 1)
getMedianByPi(piValue, eventTime = 12L, kappa = 1)
Returns a numeric value or vector will be returned.
Value that shall be converted.
The assumed time under which the event rates are calculated, default is 12.
A numeric value > 0. A kappa != 1 will be used for the specification
of the shape of the Weibull distribution.
Default is 1, i.e., the exponential survival distribution is used instead of the Weibull distribution.
Note that the Weibull distribution cannot be used for the piecewise definition of
the survival time distribution, i.e., only piecewiselambda (as a single value) and kappa
can be specified.
This function is equivalent to pweibull(t, shape = kappa, scale = 1 / lambda)
of the stats package, i.e., the scale parameter is 1 / 'hazard rate'.
For example,
getPiecewiseExponentialDistribution(time = 130, piecewiseLambda = 0.01, kappa = 4.2)
and pweibull(q = 130, shape = 4.2, scale = 1 / 0.01) provide the sample result.
Can be used, e.g., to convert median values into pi or lambda values for usage in
getSampleSizeSurvival or getPowerSurvival.