Finding probability? Please write out the calculation process, find the probability, and ask for the

The probability that he is in a library is 80% means that the probability that he is in a library is 10%, the probability that he is not in a library is 20%, and in fact he is not in 7 of them, so he is either in the eighth library or outside, so the probability in the eighth library is p = 10% (10% + 20%) = 1 3

10%, that's how I understand it.

The probability of being in the library is 80%, there are a total of eight bookstores, and there is no preference for any of them, then the probability of one of the bookstores is 10%, and there are seven found, and there is one left

In this way, there is no preference for any library, so the probability of Xiaoqiang going to any library is 80%, so the probability of his father going to the eighth library to find Xiaoqiang is still 80%. Or that no matter which library his dad goes to, the probability of finding it should be 80%.

It's just my thoughts.

The probability is 80, because his probability in the library is relative to all libraries, but Xiaoqiang's father has found seven libraries, and the research object has changed from eight to one, but Xiaoqiang's probability of being in the library remains the same, so it is still 80

Because the probability of appearing in each library is equally possible, C8 takes 1 P=80, then the probability of Xiaoqiang in a certain library is 80 8=10, so in the case that the first 7 can't be found, the probability of finding Xiao Ming in the eighth is 10

The reason is: Xiaoqiang has an 80% probability of being in the library tube, and since the first 7 are not a definite fact, then 80% is in the eighth.

Hello friends! The complete detailed and clear process RT shows, I hope it can help you solve the problem.

5+1 3, there is a bias against the solution of this problem! The process is not accurate, 4y takes it as the derivative x times is equal to 1, and y' is equal to 8

The probability of Xiaoqiang in the library is 80%, a total of 8 libraries, and the average is 10% of a library, that is: the probability of Xiaoqiang in the last library is 10%, and because there are no known seven libraries, this is a conditional probability.

Summary: The probability that Xiaoqiang is not in the library is 20%, and the probability of Xiaoqiang being in the last library is 10%, so the probability of finding Xiaoqiang in the last library is 10 (10+20)=1 3

books, the probability of him in the library is 80%, and there are 8 maps in the town.

This question should not involve the calculation mode of probability.

The chance of finding Xiaoqiang in the 8th library is 100% or 0

If Xiaoqiang must be in a library in town, then the probability that his father will find Xiaoqiang in the 8th library is 100%; If Qiang is not in the library, the probability of finding him in the 8th library is 0

Let x=1 mean heads, x=0 means tails, and the probabilities are 1 2, then ex=,dx=

Let the toss be n times, then x'=(x1+x2+..xn) n denotes the frequency of positive occurrences, ex'=,dx'=

Topic requirements. p(

p(│x'<<>1-p(│x'<<

p(│x'><

According to Chebyshev's inequality, p( x'><

Solution: n>

Therefore, at least 250 throws can make the frequency of the positive occurrence fall in (, the probability of the interval is not less than ?.

The process of solving the problem of the central limit.

Let x=1 mean heads, x=0 means tails, and the probabilities are 1 2, then ex=,dx=

Let the toss be n times, then x'=(x1+x2+..xn) obeys the central limit law, i.e. (x'-n*,1)

The frequency of positive occurrence falls on (, interval: <(x'-n*<>x'-n*<>

n^(1/2)/5<(x'-n*

n^(1/2)/5)-фn^(1/2)/5)>>2ф(n^(1/2)/5>>

n^(1/2)/5)>>n^(1/2)/5=>n^(1/2)=5*

n = Personally, I think that Chebyshev's inequality is too broad and the results are too large, while the central limit law is too idealistic, and the results are too optimistic, and the central limit law is suspected of being a circular argument. Because what number of times do you have to satisfy the central limit law ... Therefore, the number of counter-requests may not be appropriate...

If it is practical work, when the first conclusion.

Using c(n,k) to denote the number of combinations of k from n positions, then there is:

The probability of an all-red is c(5,5) c(10,5) ;

The probability of four reds is c(5,4)c(5,1) c(10,5) ;

The probability of three reds is c(5,3)c(5,2) c(10,5);

The probability of two reds is c(5,2)c(5,3) c(10,5) ;

The probability of a red is c(5,1) c(10,5) ;

The probability of being completely black is c(5,5) c(10,5).