For the following questions answer them individually
If $$\sigma$$ is the standard deviation of $$x_1, x_2, ...... x_n$$, then the standard deviation of $$9 + 3x_1, 9 + 3x_2, ....., 9 + 3x_n$$ is
A number is selected at random from the first 80 natural numbers. The probability that it is divisthle by 4 or 6 is
Two fair dice are rolled. The probability that the sum of the numbers on the faces shown is 8 is
The probability that either of the events A and B to happen is 0.6 and the probability that both of them to happen is 0.2. Then P(A‘) + P(B') =
(Here A’ is the complementary event of A.)
Suppose f(x) = (x - 2)(x - 5)(x - 7).
If a number $$\alpha$$ is chosen from {1, 3, 4, 5, 6, 7, 8, 9, 10} randomly, the probability that it satisfies the equation $$f(\alpha) = 0$$, is