Normal distribution, binomial distribution and sample distribution are commonly used in psychological and educational statistics. ① Normal distribution is a probability distribution of continuous random variables, and its distribution curve is symmetrical, and the symmetry axis is the vertical line passing through the average point. The center point of the normal distribution curve is the highest, and the area under the normal distribution curve is 1. (2) Binomial distribution refers to the probability distribution with only two different results in the experiment, which is a discrete distribution, and is mainly used to solve problems with contingency, such as guessing. ③ Sampling distribution refers to the distribution of sample statistics, which is an important basis for statistical inference. Common sampling distributions are Z distribution, χ2 distribution, T distribution and F distribution.