Q1.
- (a) The standard deviation of the expo-
3. Let the random variables X and Y have nential distribution of joint density function given by fX
(x) = \begincases λ e-λ x, & x ≥ 0 \\ 0, & x < 0 \endcases is fX,Y(x,y) = \begincases c(1-y), & 0 ≤ x ≤ y ≤ 1 \\ 0, & \textotherwise \endcases Then the marginal density function for (1)/(λ) X is (a) fX
(x) = 61/2-x-(x2)/(2)) for 0 ≤ x ≤ 1 - (c) (3)/(23) (b) fX
(x) = 61/2 + x + (x2)/(2)) for 0 ≤ x ≤ 1 - (d) (2)/(33)
(c) fX
(x) = 61/2 + x-(x2)/(2)) for 0 ≤ x ≤ 1