The Role of Probability. Basic Concepts of Probability. A probability is a number that reflects the chance or likelihood that a particular event will occur. Probabilities can be expressed as proportions that range from 0 to 1, and they can also be expressed as percentages ranging from 0% to 100%.
Thus, when people hypoventilate (i.e. causing an increase in CO2) this causes the pH in your blood to decrease, making it more acidic. (and when hyperventilation occurs, O2 is increased, which causes an increase in pH - making blood more basic).
Definition of Hypoventilation. Hypoventilation: The state in which a reduced amount of air enters the alveoli in the lungs, resulting in decreased levels of oxygen and increased levels of carbon dioxide in the blood. Hypoventilation can be due to breathing that is too shallow (hypopnea) or too slow (bradypnea), or to diminished lung function. The opposite of hypoventilation is hyperventilation (overbreathing).