Probability basics
Probability is all about uncertainty. For example, if we flip a normal coin, we're never sure if it will land on one side or the other (heads or tails). However, we can estimate the probability of the coin landing on heads with a probability function.
The simple frequentist definition of probability and a probability function is that we count the number of times the desired event happens over the total number of outcomes. In the case of a coin toss, we could flip the coin 10 times, count the number of heads, and divide by 10. Most of the time we will have something close to 5/10, or 50%. So, our probability function could be thought of as each coin flip (action, or event) resulting in a 50% chance of landing on heads (our desirable outcome). We can write the equation for our probability function as and . Our total probability across all possible (discrete) events must sum to 1 in probability theory, as it does here.
Figure 8.1: The probabilities...