A BMX biker in a white and blue helmet rides in front of some blue and black boxes .
There is a better than even chance that a BMX biker practices his tricks while wearing his helmet .
There is a better than even chance that a BMX biker practices his tricks while wearing his helmet .
It is improbable that a BMX biker practices his tricks while wearing his helmet .
A BMX biker practices his tricks while wearing his helmet .