2. In the case of geometric probability, it can be the length and area of a line segment, or it can be the area volume divided by the total length, area and volume.

3. The right end of the first equal sign should be in the probability 1- (intersection without events), that is, 1- (probability without events), not 1- (union without events).

4. Use the random variable x to record whether the event A occurs, if X= 1, otherwise X=0. Then x obeys the distribution of 0- 1 Let x 1.x2...xn be a sample, and p{x=xi}=pxi power *( 1-p)( 1-xi) power, and find the likelihood function, logarithm and derivative.

5. Solution: p (b | a) = [p (ab)]/[p (a)] =1/4 can be obtained from the conditional probability formula.

For example:

P(AC)+P(BD)=？

p(A)= A/(A+b)；

p(C | baiA)=(a- 1)/(a- 1+b)；

P(AC)= P(A)P(C | A)=(A/(A+b))*(A- 1)/(A- 1+b)

p(B)= B/(a+B)；

p(D | B)=(B- 1)/(a+B- 1)

p(BD)=(b/(a+b))*((b- 1)/(a+b- 1))

P(AC)+P(BD)=(a/(a+b))*(a- 1)/(a- 1+b)+(b/(a+b))*((b- 1)/(a+b- 1))

Extended data:

Introduce "probability" into the quantification of event possibility. Is there a stable value for the total number of independent repetitions n, event A frequency μ, event A frequency Fn(A)=μ/n, and event A frequency Fn(A)? If yes, the stable value p of the frequency μ/n is called the probability of the occurrence of event A, and it is recorded as P(A)=p (statistical definition of probability).

P(A) is objective, while Fn(A) depends on experience. In statistics, the value of Fn(A) is sometimes used as an approximation of probability when n is large.

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