We know that the probability of getting a head in a single coin is:
[tex]p=0.5[/tex]Now, we can calculate the probability of X out of N coins landing heads up with the binomal distribution:
With p = 0.5 and N = 4, we get:
Subtituting X = 1 ("getting one head"), we get that:
[tex]P=0.0625[/tex]