(1) To estimate the power of testing for linkage using an affected sib pair design, as a function of the recurrence risk ratios. We will use analytical power formulae as implemented in R. These are based on a Mathematica notebook created by Martin Farrall. (2) To examine how the power of the transmission disequilibrium test (TDT) depends on the disease allele frequency, the marker allele frequency, the strength of the linkage disequilibrium, and the magnitude of the genetic effect. We will use an R program that implements the power formulae of Abel and Muller-Myhsok (1998). These formulae allow one to quickly compute power of the TDT approach under a variety of different conditions. This R program was modeled on Martin Farrall's Mathematica notebook.
|Author||Daniel E. Weeks|
|Date of publication||2012-10-11 18:57:17|
|Maintainer||Daniel E. Weeks <email@example.com>|
|License||GPL (>= 2)|
fnfam: Internal function called by ntdt
fx: Internal function for the ptdt function
normplot: Power plotting demonstration
nsibs: A function to compute power of an affected sib pair design.
ntdt: Computes number of trios needed for a TDT study.
ntdt.q: Computes power of a TDT study as a function of the...
plotDom: plotDom creates power graphs for an affected sibpair linkage...
plotNsibs: plotNsibs: Create power plots for an affected sib pair...
plotNtdt: A function for plotting the results from ntdt.q
ptb: A power table for the TDT design
ptdt: Power for a TDT design