Normal distribution If the probability density of continuous random variable X is

Where μ, σ (σ >; 0) is a constant, then X is said to obey the normal distribution or Gaussian distribution with the parameters μ, σ.

1, the curve is symmetrical about x=μ. This shows that for any H >；; 0

2. Take the maximum value when x = μ.

The farther x is from μ, the smaller the value of f(x). This shows that for the interval with the same length, when the interval is far from μ, x? The smaller the probability of falling within this range.

When x = μ a, the curve has an inflection point. The curve is a cow? The axis is an asymptote.