Total number of camera = 7
Defective camera = 5
Sample selected = 2
when x = 0
P(x=0) = 2/7 × 1/6 = 2/42
P(x=1) = [2/7 × 5/6] + [5/7 × 2/6] = 20/42
P(x=2) = 5/7 × 4/6 = 20/42
So,
E(x) = [0×2/42] + [1×20/42] + [2×20/42]
E(x) = 1.43
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