STA 119 Lecture Notes - Lecture 5: Physical Therapy, Drawing Pin
Document Summary
Probability is a measure of how likely an event is to occur. When we toss a coin, we say tossing a heads is 50/50, meaning we think a heads will occur. We say this because there are 2 sides to the coin and by the symmetry of the coin, we feel that each side has an equal chance of occurring. When the weatherman says that there is 70% chance of rain tomorrow, we understand that to mean that based on similar weather patterns in the past, it has rained about 70% of the time. We need to assign probabilities to the outcomes 1 - 6 so that each probability is greater than or equal to 0 and so that the total probability is 1. By the symmetry of the die, we could reasonably expect that each side is equally likely to occur.