Answer:
The probability that a baby born with Down's syndrome is a boy is .
Step-by-step explanation:
The probability of a baby born being a boy (B) or a girl (G) is same, i.e.
P (B) = P (G) = 0.50.
The probability of a boy is born with Down's syndrome is, P (D|B) = <em>p</em>.
The probability of a girl is born with Down's syndrome is, P (D|G) = <em>q</em>.
The law of total probability states that:
Use this law to compute the probability of a baby born with Down's syndrome as follows:
The conditional probability of an event <em>X</em> given that another event <em>Y</em> has already occurred is:
Compute the probability that a baby born with Down's syndrome is a boy as follows:
Thus, the probability that a baby born with Down's syndrome is a boy is .