Probability and statistics of your problem design.

First of all, explain:

The consciousness x of X~B(n, p) obeys binomial distribution.

EX is the average or mathematical expectation of x. There are many situations in the numerical value.

When x meets the two-point distribution, EX=np (this is also required in the exam, not required in other exams, but occasionally there are joint exercises, and it is not too late to sum up)

When x satisfies the binomial distribution, that is, X~B(n, p), then ex = x1* p1+x2 * p2+```````+xn * pn, where Xi is the value of each term and pi is the corresponding probability of the term.

DX is the variance, and there are many cases in the branch.

In the binomial distribution you mentioned, DX=np( 1-P).

I am honored to answer your questions and hope to adopt them ~