Probability Definition. The probability of an event is a number between $0$ to $1$ which measures the chance of that event occurring. The likelihood of the occurrence of the event increases as the probability varies from $0$ to $1$. The probability of the occurrence of an impossible event is $0$ and that of a certain to occur event is $1$.
As altitude increases, air pressure decreases. Gravity causes the atmosphere to become heavier the closer you are to the ground. The atmosphere may seem weightless but all the â¦ air molecules add up to a tremendous amount of mass.
This temporarily increases blood pressure until the body adapts to the lower oxygen level, usually within a couple of days. The rule of thumb for spending time at a higher altitude is to go no higher than 8,000 feet in the first leg of the trip, and stay there for at least one night.