Question

There are 4 cards numbered 1 to 4,one number on one card. Two cards are drawn at random without replacement. Let X denete the sum of the numbers on the two drawn cards. Find the mean and variance of X ?​

Answer 1

Step-by-step explanation:

The 4 cards are numbered as 1,3,5,7

Let S be the sample space and we have 4×3=12 elements in sample space

Here X is sum of numbers on two drawn cards , X can be 4,6,8,10,12

P(X=4)=122=61

P(X=6)=122=61

P(X=8)=124=31

P(X=10)=122=61

P(X=12)=122=61

∑PiXi=4×61+6×61+8×31+