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The mean of the numbers obtained on throwing a die having written 1 on three faces, 2 on two faces and 5 on one face is
Given: A die having written 1 on three faces, 2 on two faces and 5 on one face.
Let X be the random variable representing a number on given die.
Then X can take any value of 1, 2 or 5.
The total numbers is six.
Now
P(X = 1)
P(X = 2)
P(X = 5)
Hence, the required probability distribution is,
X | 1 | 2 | 5 |
P(X) |
Therefore Expectation of X E(X):
⇒ E(X) = 2
Hence, the correct answer is (B).
A random variable X has the following probability distribution:
X | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
P(X) | 0 | k | 2k | 2k | 3k | K2 | 2 K2 | 7 K2 + k |
Determine
(i) k (ii) P(X < 3)
(iii) P(X > 6) (iv) P(0 < X < 3)