v0=sample(c(T,F),100,T)
df = data.frame(v0=v0, v1=rnorm(100,0,1) + v0*rnorm(100,1,1),v2=rnorm(100,2,1))
v0=sample(c(T,F),100,T)
df = data.frame(v0=v0, v0=sample(c(T,F),100,T)
df = data.frame(v0=v0, v1=rnorm(100,0,1) + v0*rnorm(100,1,1),v2=rnorm(100,2,1))
v0=sample(c(T,F),100,T)
df = data.frame(v0=v0,