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12. A distributor of fruit basket is going to put 4 apples, 6 oranges and 2 bunc

ID: 3356550 • Letter: 1

Question

12. A distributor of fruit basket is going to put 4 apples, 6 oranges and 2 bunches of grapes in his small gift basket. The weights, in ounces, of these items are the random variables Xi, X2 and X3 respectively with means and standard deviation given in the table below Apples Oranges Grapes Mean ()8 10 7 SD (o 0.91.1 Find the mean, variance and standard deviation of the random variable Y, which is weight of fruit in a small gift basket. Assume the weights of different types of fruits are independent (a) E(Y) = 104 ; Var(Y) = 78.49 ; SD (Y) = 5.8959 (b) E(Y) = 88 ; Var(Y) = 42.82 ; SD (Y) = 3.1257 (c) E(Y) = 106 ; Var(Y) = 72.52 ; SD (Y) = 8.5159 (d) E(Y) = 120 ; Var(Y) = 82.72 ; SD (Y) = 9.2316

Explanation / Answer

Y = 4X1 + 6X2 + 2X3

E(Y) = 4*E(X1) + 6*E(X2) + 2*E(X3)

= 4*8 + 6*10 + 2*7

= 106

V(Y) = 42 * V(X1) + 62 * V(X2) + 22 * V(X3)

= 16 * 0.92 + 36 * 1.12 + 4 * 22

= 72.52

Sd(Y) = sqrt(72.52) = 8.5159

Option-C) is the correct answer