Standard Normal Distribution

This is a continuous distribution.
Also known as the Z distribution
There is a special type of normal distribution called the standard normal deviation which has a mean of 0 and a standard deviation of 1.
The variable typically used for denoting a standard normal random variable is "z" (lowercase z)

Excel Functions

NORM.S.DIST - Returns the probability of getting 'less than' or 'equal to' a particular value in a standard normal distribution.
NORM.S.INV - Returns the random variable where the probability of getting 'less than' it is equal to P in a standard normal distribution.

This function returns the cumulative distribution P(x <= X)