Two cards are drawn simultaneously from well shuffled pack of 52 cards, then mean and variance of number of red cards are :
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 1,25/51
The expected value (mean) is,
$E(x)=n×\frac{k}{N}=2×\frac{26}{52}$
$=2×\frac{1}{2}=1$
The variance,
$Var(x)=n×\frac{k}{N}×\frac{N-k}{N}×\frac{N-n}{N-1}$
$=2×\frac{26}{52}×\frac{26}{52}×\frac{50}{51}$
$=\frac{25}{51}$