udPar function

Representing Wei's Urn Design

Represents Wei's Urn Design.

udPar(N, ini, add, groups = LETTERS[1:2])

Arguments

• N: integer for the total sample size of the trial.
• ini: integer representing the initial urn composition.
• add: integer representing the number of balls that are added to the urn in each step.
• groups: character vector of labels for the different treatments.

Returns

S4 object of the class udPar.

Details

An urn is filled with a number of ini balls of both of the treatments. Afterwards, a ball is drawn randomly from the urn. Finally, add balls are added to the urn from the opposite treatment. This procedure is repeated until N patients are assigned.

References

L.J. Wei (1977) A Class of Designs for Sequential Clinical Trials. Journal of the American Statistical Association, 72 , 382-6.

See Also

Other randomization procedures: abcdPar, bbcdPar, bsdPar, chenPar, crPar, createParam(), ebcPar, gbcdPar, hadaPar, mpPar, pbrPar, rarPar, rpbrPar, rtbdPar, tbdPar