Distribution function of normal distribution: If the random variable X obeys a probability distribution with the position parameter μ and the scale parameter σ σ, its probability density function is f(x)= 12π√σe(xμ)22σ2.

If the random variable X obeys the normal distribution with a mathematical expectation of μ and a variance of σ 2, it is recorded as N(μ, σ 2). The expected value μ of probability density function with normal distribution determines its position, and its standard deviation σ determines its distribution amplitude. When is μ? =? 0,σ? =? The normal distribution at 1 is a standard normal distribution.

Characteristics of normal distribution characteristic function;

1) concentration: the highest peak of the curve is located in the center, and the position is where the average value is located.

2) Symmetry: the normal distribution curve is symmetrical around the mean position, and the two sections of the curve wirelessly approach the horizontal axis.

3) Uniform variability: the normal distribution curve drops to the left and right sides evenly around the mean position.

4) The area between the curve and the horizontal axis is always equal to 1.