Question

Out of $2000$ families with $4$ children, the number of families you expect to have two male children

• A. $1875$
• B. $750$
• C. $1250$
• D. $625$

Answer 1

Answer: (B)

$750$

The probability of $4$ families having two boys will be
${}^4{C}_2(\frac{1}{2}{)}^4$
$=\frac{6}{16}$
Hence the expected frequency for $2000$ families is
$=2000\left(\frac{6}{16}\right)$

$=125\left(6\right)$
$=750$