plotNsibs {powerpkg}

plotNsibs: Create power plots for an affected sib pair linkage study

Description

Plots the required sample sizes needed to detect linkage in an affected sib pair linakge study as a function of lambda sib, under the assumption that lambda sib = lambda off.

Usage

plotNsibs(alpha = 0.001, power = 0.85,...)

Arguments

alpha

the Type 1 error rate (significance level).

power

the power to detect linkage.

...

additional arguments for plot

Details

Assumes that lambda sib = lambda off.

Value

Creates a plot, and returns a table of the data that generated the plot. In this table, the first column gives the lambda sib value, while the second column gives the corresponding number of affected sib pairs needed to have the desired power.

Warning

Makes the simplifying assumptions that (1) all families will have exactly two affected sibpairs; and that (2) the identity-by-descent status in the ASPs can be determined unambiguously

Note

These are based on a Mathematica notebook created by Martin Farrall.

Author(s)

Daniel E. Weeks

See Also

nsibs, plotDom

Examples

## Plot the required sample sizes in an affected sib pair linkage study as
## a function of lambda sib required to have 85 percent power at an alpha 
## level of 0.001, under the assumption that lambda sib = lambda off.

plotNsibs(alpha=0.001,power=0.85)