CI.RatioF  R Documentation 
Utility function to calculate the 1–2α Fieller confidence interval given the point estimate, CV (, CVb), and n for the parallel group and 2×2 crossover.
CI.RatioF(alpha = 0.025, pe, CV, CVb, n, design = c("2x2", "parallel"))
alpha 
Type I error probability, aka significance level. 
pe 
Point estimate of T/R ratio. 
CV 
Coefficient of variation as ratio (not percent). In case of 
CVb 
CV of the betweensubject variability. Only necessary for

n 
Total number of subjects if a scalar is given. 
design 
A character string describing the study design. 
The CV(within) and CVb(etween) in case of design="2x2"
are
obtainedvia an appropriate ANOVA from the error term and from the
difference (MS(subject within sequence)MS(error))/2
.
Returns the 1–2α confidence interval.
The function assumes an evaluation using untransformed data.
The function assumes equal variances in case of design="parallel"
.
The formula implemented covers balanced and unbalanced designs.
Note that when the mean of the denominator of the ratio is close to zero,
confidence intervals might be degenerated and are returned as NA
. In such
a case a warning is issued.
Whether the function vectorizes properly is not thoroughly tested.
This function is intended for studies with clinical endpoints. In such
studies the 95% confidence intervals are usually used for equivalence
testing. Therefore, alpha defaults here to 0.025 (see EMA 2000).
D. Labes
Locke CS. An exact confidence interval from untransformed data for the ratio of two formulation means. J Pharmacokin Biopharm. 1984;12(6):649–55. doi: 10.1007/BF01059558
Hauschke D, Steinijans VW, Pigeot I. Bioequivalence Studies in Drug Development. Chichester: John Wiley; 2007. Chapter 10. doi: 10.1002/9780470094778.fmatter
European Medicines Agency, Committee for Proprietary Medicinal Products. Points to consider on switching between superiority and noninferiority. London, 27 July 2000. CPMP/EWP/482/99
CI.BE
, power.RatioF
# 95% Fieller CI for the 2x2 crossover CI.RatioF(pe = 0.95, CV = 0.3, CVb = 0.6, n = 32)
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