A drawer contains 8 brown socks and 4 blue socks. A sock is taken from the drawer at random, its colour is noted and it is then replaced. This procedure perform twice more. If X is the random variable. “the number of brown socks taken “,
a) Construct the probability distribution table (5M)
b) Compute E(X) (6M)
c) Calculate E (5X +3) (4M)
d) Calculate VAR (X) (5M)
5 answers
no idea
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<p>Test</p>
Please solve this question
X: variable random
So 8 brown socks plus 4 blue socks in the drawer=12 socks
Let assume that P(no brown socks) means P(X=0)=(4/12)³ must be equal to 1/27
P(X=1)=[8/12(4/12)² +(4/12)²8/12 +(4/12×8/12×4/12)]=6/27
P(X=2)= 3(8/12×8/12×4/12) =4/9
P(X=3) =3(8/12)³ =8/27
So 8 brown socks plus 4 blue socks in the drawer=12 socks
Let assume that P(no brown socks) means P(X=0)=(4/12)³ must be equal to 1/27
P(X=1)=[8/12(4/12)² +(4/12)²8/12 +(4/12×8/12×4/12)]=6/27
P(X=2)= 3(8/12×8/12×4/12) =4/9
P(X=3) =3(8/12)³ =8/27
1 answer