# Inverse of Normal Distribution CDF incorrect for large value?

I have a function F which is the CDF of the standard normal distribution. The inverse of F should be infinity at 1. However, I got 8.52 for below:

F[x_] := CDF[NormalDistribution[0, 1], x];
N@InverseFunction[F[#] &][1/2/0.5]


If I amend my code to N@InverseFunction[F[#] &][1], the output would even give me a complex number.

Why is the result of 1 different to 1/2/0.5?

How can I force it to produce the correct result?

• Actually, why are you not using InverseCDF[] or Quantile[]? InverseCDF[NormalDistribution[], 1/2/0.5] – J. M.'s technical difficulties Sep 26 '18 at 2:17
• Thanks. It works well. – H42 Sep 26 '18 at 5:04