InterviewSolution
Saved Bookmarks
| 1. |
Let a pair of dice be thrown and the random variable X be the sum of the numbers that appear on the two dice. Find the mean or expectation of X. |
|
Answer» let `x` be the sum of numbers on the two dice `x= 2 ; p(2) = 1/36` `x=3 ; p(3) = 2/36` `x=4 ; p(4) = 3/36` `x=5 : p(5) = 4/36` `x=6 ; p(6) = 5/36` `x=7 ; p(7) = 6/36` `x=8 ; p(8) = 5/36` `x=9 ; p(9)= 4/36` `x=10 ; p(10)= 3/36` `x=11 ; p(11) = 2/36` `x=12 ; p(12) = 1/36` mean = `sum x p(x)` `= 2/36 + 3*2/36 + 4*3/36 + 5*4/36 + 6*5/36 + 7*6/36 + 8*5/36 + 9*4/36 + 10*3/36 + 11*2/36 + 12*1/36` `= 252/36 =7` answer |
|