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20 13 mathematics questions and answers in the college entrance examination
(1), the antonym of which is "A has neither received the notification information from Miss Li nor Miss Zhang", p =1-{(n-k)/n} 2 = (2nk-k 2)/n 2.

(2) Remember that X(i)= 1, and the I-th student in the department received the message from Miss Li or Miss Zhang.

=0, the I-th student in the department has not received the information from Miss Li and Miss Zhang, so X=∑X(i), (I = 1, 2,3,4 ... k), and X(i) is independent of each other, so X~B(n, p) binomial distribution (i.e. N-fold Bernoulli experiment) Obviously, k < = m < = 2k,,,,

The above answers are for reference only!