Significance testing in ridge regression for genetic data

Table 4 Comparison of computational performance

	Approximate test	Permutation test
time (seconds)	1.936	1043.604

Comparison of computation performance of approximate test and permutation test. n = 1000, m = 1000 and λ = 1. Approximate test and permutation test p - values were computed and the time taken to arrive at the p-values was recorded. Calculations were done using R version 2.12.0 [27] on an iMac running Mac OS X Version 10.6.7, fitted with an 2.8 Ghz Intel Core i7 processor and 16 GB 1067 MHz DDr3 RAM.