Utility function to calculate the
Fieller confidence interval given the point estimate, CV (, CVb), and n for the parallel group and
crossover.
CI.RatioF(alpha = 0.025, pe, CV, CVb, n, design = c("2x2", "parallel"))Type I error probability, aka significance level. Defaults here to 0.025 because this function is intended for studies with clinical endpoints.
Point estimate of ratio T/R.
Coefficient of variation as ratio (not percent). In case of design="parallel"
this is the CV of the total variability, in case of design="2x2"
the intra-subject CV.
CV of the between-subject variability. Only necessary for
design="2x2".
Total number of subjects if a scalar is given. Number of subjects in (sequence) groups if given as vector.
A character string describing the study design.
design="parallel" or design="2x2" allowed for a
parallel two-group design or a classical TR|RT crossover design.
Returns the confidence interval.
The CV(within) and CVb(etween) in case of design="2x2" are
obtained via an appropriate ANOVA from the error term and from the
difference (MS(subject within sequence)-MS(error))/2.
Locke CS. An exact confidence interval from untransformed data for the ratio of two formulation means. J Pharmacokin Biopharm. 1984;12(6):649--55.
Hauschke D, Steinijans VW, Pigeot I. Bioequivalence Studies in Drug Development. Chichester: John Wiley; 2007. Chapter 10.
European Medicines Agency, Committee for Proprietary Medicinal Products. Points to consider on switching between superiority and non-inferiority London, 27 July 2000. CPMP/EWP/482/99
# NOT RUN {
# 95% Fieller CI for the 2x2 crossover
CI.RatioF(pe=1.05, CV=0.3, CVb=0.6, n=24)
# }
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