Binomial distribution (Bernoulli probability type), the variance np of mathematical expectation NP (1-p);

Poisson distribution, mathematical expectation λ variance λ;

Uniform distribution, mathematical expectation (a+b)/2 variance [(b-a) 2]/12;

Exponential distribution, mathematical expectation 1/λ variance1/λ 2;

Normal distribution, mathematical expectation μ variance σ 2;

Standard normal distribution, mathematical expectation 0 variance 1