1.Find the mean and the variance of the uniform probability distribution given by f(x) = 1/n for x =1,2,3,4.....,n [hint: the sum of the first n positive is n(n+10)/2 , and the sum of their squares is n(n+1)(2n+1)/6] 2.In 1 out 6 cases,material for bulletproof vests fails to meet puncture standards. If 405 specimens are tested, what does Chebyshev's theorem tell us about the probability of getting at most 30 or more than 105 cases that do not meet puncture standard? 老實說第二題我根本就不太懂他要衝蝦米 唉 -- http://www.wretch.cc/album/bestbestasan --

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