In reply to Carol Troy.

I think you and I have the same formula. In my notation, "Capital Phi" is the one-dimensional CDF with parameters μ and σ. The notation Φ(y; ρx, sqrt(1-ρ^2)) indicates the 1-D normal CDF for variable y, where the parameters μ=ρx and σ=sqrt(1-ρ^2) follow the semicolon. I think from your formula that you were expecting Phi to be the standard CDF. I could have (should have?) used a letter other than Phi to represent the non-standardized cumulative normal distribution, so thanks for pointing out the potential for confusion.