If you are looking to find the probability of a value is not exactly or more than a fixed positive z value then you can find the value with the help of a std normal distribution table. The normal distribution density function f(z) is called the Bell Curve as its shape looks like a bell.

The std normal distribution table is used to examine the area under the bend (f(z)) to find the probability of a particular range of distribution. It is appropriate only for the positive values of Z. The normal distribution also known as Gaussian distribution is a continuous probability distribution. The std normal distribution table shows the probability of a continuous distributed random variable Z, whose mean value is equal to 0 and the value of standard deviation equal to one.The mean of standard normal distribution is always equal to its median and mode. In probability theory, the normal or Gaussian distribution is the most significant continuous probability distribution. In the standard normal distribution formula given above, It is possible to change each normal random variable X into a z score through the following standard normal distribution formula The random variable of a standard normal curve is known as the standard score or a Z-score. The mean of standard normal distribution is always equal to its median and mode.

It appears when a normal random variable has a mean value equals zero and the value of standard deviation equals one. The standard normal distribution is a type of normal distribution.

Standard normal table z scores