(1) Selection of sampling method, calculation related to sample size, especially related calculation in stratified sampling, A-level requirements.

(2) Histogram and stem leaf diagram in the chart can be used as inspection points, especially the histogram is a hot spot, which requires A grade.

(3) The calculation of variance and standard deviation in feature number is a hot topic, which is required by Grade B. 。

(4) Probability calculation of random events, usually in the form of classical probability and geometric probability, requires Class B. 。

1. Probability problem

(1) When solving some complicated probability problems, there are usually two methods: one is to decompose them into the sum of several mutually exclusive events, and then use the probability addition formula to find their values; The second is to find the probability of the negative event A of this event A, and then use p (a) = 1-p (a) to solve it;

(2) List the basic events of the classical probability test one by one by enumeration method, then find out the basic events in event A, and calculate the probability of event A by formula p (a) = Mn, which is a good visual method, but it must be listed in a certain order, and no repetition or omission is allowed;

(3) The most critical step to find the probability of geometric probability is to find the measure of the area occupied by the basic event contained in event A. Here, it is necessary to analyze the knowledge of geometry, and the most difficult thing is to find the constraint conditions of the basic event.

2. Statistical issues

(1) Statistics main processing data. In order to ensure the objectivity and fairness of statistics, sampling is a necessary and important part of statistics. There are three sampling methods: simple random sampling, systematic sampling and stratified sampling;

(2) The key points of estimating the overall distribution with sample frequency distribution are: drawing frequency distribution table and frequency distribution histogram, and estimating the overall distribution with sample frequency distribution, but the difficulties are: understanding and application of frequency distribution table and frequency distribution histogram;

(3) The advantage of using the stem-leaf diagram is that the original information will not be erased, which can expand the data release, but when there are more sample data or more data bits, the stem-leaf diagram is inconvenient;

(4) In the correlation between two variables, we can mainly make a scatter plot, understand the idea of least square method, and establish a linear regression equation according to the given coefficients or formulas of linear or regression equations.