list( y = c( 0.3344302, NA, 0.6064218, -0.1142923, -0.8411741, 0.714253, 
-0.3539002, 0.7501046, 1.111303, -0.3737974) , x1 = c(NA, 2.221932, 
NA, 0.5613883, -1.743889, 1.732425, -1.176768, -0.2809368, 2.501798, 
-2.100418) , x2 = c( 0.2917086, 1.842547,NA, -0.1232346, -0.8034306, 
0.8855344, -1.356287, 1.929182, 1.124483, -0.4706626), N=10)