seq_anderson_preece: Anderson and Preece (2002) cross-over design specification
In mjg211/xover: Design and analysis of cross-over clinical trials

Description Usage Arguments Details Value Author(s) References Examples

Specifies a cross-over design from Anderson and Preece (2002).

1	seq_anderson_preece(labels = 0:6, as_matrix = T, summary = T)

`labels`	A `vector` of labels for the treatments. Should be of `length` seven, containing unique elements. Defaults to `0:6`.
`as_matrix`	A `logical` variable indicating whether the design should be returned as a `matrix`, or a `tibble`. Defaults to `T`.
`summary`	A `logical` variable indicating whether a summary of the function's progress should be printed to the console. Defaults to `T`.

seq_anderson_preece() supports the specification of a cross-over design from Anderson and Preece (2002). Sequences are supported for any chosen treatment labels (see labels). In addition, the design can be returned in matrix or tibble form (see as_matrix).

Precisely, a set of 42 sequences are returned, for a design with seven periods and seven treatments. Ultimately, the (k,j)th element of the cross-over design matrix corresponds to the treatment a subject on the kth sequence would receive in the jth period.

Either a matrix if as_matrix = T (with rows corresponding to sequences and columns to periods), or a tibble if as_matrix = F (with rows corresponding to a particular period on a particular sequence). In either case, the returned object will have class xover_seq.

Based on data from the Crossover package by Kornelius Rohmeyer.

Anderson I, Preece DA (2002) Locally balanced change-over designs. Utilitas Mathematica 62:33-59.

# Anderson and Preece (2002) design for the default parameters
anderson_preece         <- seq_anderson_preece()
# Using different labels
anderson_preece_ABCDEFG <- seq_anderson_preece(labels = LETTERS[1:7])
# Returning in tibble form
anderson_preece_tibble  <- seq_anderson_preece(as_matrix = F)