Jan 25, 2007

A derivation for Armitage's trend test for the 2x3 genotype table

Feb 6, 2007

A very short R code for testing HWE Measures of Linkage Disequilibrium

March 15, 2007

In this section we show the derivation of D' and the relationship between D' and R.
Part I: A Development of the LD Measure D'

Part II: A Development of the LD Measure R

Part III: The Relationship Between D' and R

June 5, 2007

Some R code to do a quick sample size estimate for genetic association using case-control studies. Please note that this code contains a parameter that can be adjusted to allow sample size correction under the assumption that the p-values will be adjusted with the Bonferronni correction. A drawback is that the code assumes that the researcher knows the mode of inheritance of the trait.

June 6, 2007 Some R code to do a quick power curve for genetic association using case-control studies. Given the accepted probability of Type I error, disease prevalence, mode of inheritance, and sample size, this returns a curve of power vs. relative risk given 2 disease alleles. Please note that this code contains a parameter that can be adjusted to allow power estimate under the assumption that the p-values will be adjusted with the Bonferronni correction. A drawback is that the code assumes that the researcher knows the mode of inheritance of the trait. Result of running the code will be a graphic like the one shown below.