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.
Andy Schleck during stage 1 of the 2009 Tour de France. Training at altitude may help athletes gain a competitive edge at sea level; altitude exposure also presents problems to athletes, and these could possibly cancel out benefit. Even moderate altitudes can have a significant effect on athletic performance.Click to see the effects on physical performance at altitude.he âlowâ altitudes may not actually be at sea level, but could be 1250m, for example. However, the difference between the two altitudes is significant enough to have an effect on training [see the difference in oxygen and pressure at these altitudes with our high altitude calculator].