There are three compulsory chapters in senior high school mathematics: statistics, preliminary algorithm and probability. Most of them are written down and memorized, and there are few formulas.

statistics

① Probability = sample capacity ÷ total capacity?

② Number of stratified samples = I layers ÷ total number of samples × sample size.

③ Sampling distance = total number ÷ number of samples.

④ Average x=(x 1+x2+x3++xn)/n

⑤ Variance S 2 = [(x1-x) 2+(x2-x) 2+...+(xn-x) 2]/n

⑥ Standard deviation = root sign (s 2)

⑦ linear regression equation y=bx+a

2. Preliminary algorithm

This part of the formula mainly includes algorithm block diagram and algorithm statement (divided into sequence structure, selection structure and cyclic structure).

3. Possibility

The probability calculation formula of classical probability: p (a) = the number of basic events contained in a ÷ the total number of basic events.

Probability formula of geometric probability: P(A)= the length (area, volume) of the region that constitutes the A event ÷ the length (area, volume) of the region that constitutes the total event.

Mutually exclusive events p (a1+a2) = p (a1)+p (a2).

Opposite event P(A)= 1-P(A)