PowerTOST (version 1.5-6)

CI.RatioF: 1--2*alpha Fieller CI given point estimate, CV (, CVb) and n

Description

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.

Usage

CI.RatioF(alpha = 0.025, pe, CV, CVb, n, design = c("2x2", "parallel"))

Value

Returns the

1–2α

confidence interval.

Arguments

alpha

Type I error probability, aka significance level.
Defaults here to 0.025 because this function is intended for studies with clinical endpoints.

pe

Point estimate of T/R ratio.

CV

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.

CVb

CV of the between-subject variability. Only necessary for design="2x2".

n

Total number of subjects if a scalar is given.
Number of subjects in (sequence) groups if given as vector.

design

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.

Author

D. Labes

Details

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.

References

Locke CS. An exact confidence interval from untransformed data for the ratio of two formulation means. J Pharmacokin Biopharm. 1984;12(6):649--55. tools:::Rd_expr_doi("10.1007/BF01059558")

Hauschke D, Steinijans VW, Pigeot I. Bioequivalence Studies in Drug Development. Chichester: John Wiley; 2007. Chapter 10. tools:::Rd_expr_doi("10.1002/9780470094778.fmatter")

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

See Also

CI.BE, power.RatioF

Examples

# 95% Fieller CI for the 2x2 crossover
CI.RatioF(pe = 0.95, CV = 0.3, CVb = 0.6, n = 32)