Answer
The required solution of probability is, $\frac{1}{4}$
Work Step by Step
Note that with 52 cards in the deck, the total number of possible ways in which a single card is dealt is 52.
Therefore, the total number of possible outcomes in the sample space is 52. That is, $ n\left( S \right)=52$
Assume, $ E $ to be the event of being dealt a diamond; then clearly $ n\left( E \right)=13$
Thus, the probability of being dealt a diamond is:
$\begin{align}
& P\left( E \right)=\frac{n\left( E \right)}{n\left( S \right)} \\
& =\frac{13}{52} \\
& =\frac{1}{4}
\end{align}$
