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Question
For the following probability distribution:
| X | – 4 | – 3 | – 2 | – 1 | 0 |
| P(X) | 0.1 | 0.2 | 0.3 | 0.2 | 0.2 |
E(X) is equal to ______.
Options
0
– 1
– 2
– 1.8
Solution
For the following probability distribution:
| X | – 4 | – 3 | – 2 | – 1 | 0 |
| P(X) | 0.1 | 0.2 | 0.3 | 0.2 | 0.2 |
E(X) is equal to – 1.8.
Explanation:
We know that
E(X) = `sum_("i" = 1)^"n" "X"_"i""P"_"i"`
= (– 4)(0.1) + (– 3)(0.2) + (– 2)(0.3) + (– 1)(0.2) + 0(0.2)
= – 0.4 – 0.6 – 0.6 – 0.2
= – 1.8
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