SOLUTION: twelve distinct positive integers are chosen without replacement from the first 50 positive integers. let x denote integer di visible by 5. 1. find E(x) and var(x)

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Question 870612: twelve distinct positive integers are chosen without replacement from the first 50 positive integers. let x denote integer di visible by 5.
1. find E(x) and var(x)
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

5, 10, 15, 20, 25, 30, 35, 40, 45, 50

E = mean = (1/10)(5+ 10+ 15+ 20+ 25+ 30+ 35+ 40+ 45+ 50)= 27.5

variance:

        x-27.5 (x-27.5)^2

5	-22.5	506.25

10	-17.5	306.25

15	-12.5	156.25

20	-7.5	56.25

25	-2.5	6.25

30	2.5	6.25

35	7.5	56.25

40	12.5	156.25

45	17.5	306.25

50	22.5	506.25

275	0	56.25 Variance = 506.25/9  (Using n-1)