A couple decides to keep having children until they have a boy, at which point they will stop having children. They also agree to having a maximum of three children. The table below shows the probability distribution of \[X=\] the number of children such a couple would have.
\[X=\# \text{ of children}\] \[1\] \[2\] \[3\]
\[P(X)\]

\[\dfrac{1}2\]

\[\dfrac{1}4\]

\[\dfrac{1}4\]
On average, how many children would such a couple have?
\[E(X)=\]

children