Sample space has 4 outcomes; $P(\text{at least 1 heads}) = \frac{1}{4}$

Sample space has 4 outcomes; $P(\text{at least 1 heads}) = \frac{3}{4}$

Sample space has 2 outcomes; $P(\text{at least 1 heads}) = \frac{1}{2}$

Sample space has 3 outcomes; $P(\text{at least 1 heads}) = \frac{2}{3}$