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.
The effects of high altitude on humans are considerable. The percentage saturation of haemoglobin with oxygen determines the content of oxygen in our blood. After the human body reaches around 2,100 m (7,000 feet) above sea level, the saturation of oxyhemoglobin begins to plummet.ountain medicine recognizes three altitude regions that reflect the lowered amount of oxygen in the atmosphere: 1  High altitude = 1,500â3,500 metres (4,900â11,500 ft). 2  Very high altitude = 3,500â5,500 metres (11,500â18,000 ft). 3  Extreme altitude = above 5,500 metres (18,000 ft).