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