a priori Probability: the probability that we determine from knowing the process by which the uncertain event happens (by logically examining existing information). Certain Event: event that is sure ...

An animated guide to probability explains how to express probability as fractions and percentages based on the ratio of the number of ways an outcome can happen and the total number of outcomes.

The theoretical probability of getting a head when you flip a fair coin is \(\frac{1}{2}\), but if a coin was actually flipped 100 times you may not get exactly 50 heads, although it should be close ...