Step 1: Understanding the Concept:
Probability is defined as the number of favorable outcomes divided by the total number of possible outcomes in the sample space.
Step 2: Detailed Explanation:
For a fair coin, the sample space $S = \{H, T\}$.
Total number of outcomes $n(S) = 2$.
Event $E$ of getting a head $= \{H\}$.
Number of favorable outcomes $n(E) = 1$.
$P(E) = \frac{n(E)}{n(S)} = \frac{1}{2}$.
Step 3: Final Answer:
The probability is 1/2.