The normal curve is bell-shaped, with low ends and high middle, which is symmetrical left and right, so people often call it bell-shaped curve.

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 μ = 0 and σ = 1, the normal distribution is standard normal distribution.

Parameter meaning:

The normal distribution has two parameters, namely the expected (mean) μ and the standard deviation σ, where σ2 is the variance.

The distribution of continuous random variables with two parameters μ and σ 2. The first parameter μ is the mean of a random variable that obeys normal distribution, and the second parameter σ2 is the variance of this random variable, so the normal distribution is recorded as N(μ, σ 2).

μ is the position parameter of normal distribution, which describes the centralized trend position of normal distribution. The law of probability is that the probability of taking a value close to μ is high, and the probability of taking a value far from μ is low. Normal distribution takes X=μ as the symmetry axis, and the left and right sides are completely symmetrical. The expectation, mean, median and mode of normal distribution are all the same, which are all equal to μ.