Understanding Basic Probability
When you roll a dice or flip a coin, you're experiencing probability in action! An outcome is any possible result of an experiment, while the sample space includes all possible outcomes. For example, rolling a dice has a sample space of {1,2,3,4,5,6}, and flipping a coin has {heads, tails}.
Theoretical probability tells us how likely something is to happen based on the number of ways it can happen divided by the total possible outcomes. We calculate it using the formula: P(A) = Number of favorable outcomes ÷ Total number of outcomes. This value always falls between 0 (impossible) and 1 or 100% (certain).
Let's look at a real example: Maria has 10 pens (3 red, 2 black, and 5 blue) in her backpack. If she randomly grabs one pen, the probability of getting a blue pen is 5/10 or 1/2 (50%), making it equally likely as not getting a blue pen. The probability of getting a black pen is only 2/10 or 1/5 (20%), making it less likely than other colors.
Try This! If you have a standard deck of 52 playing cards, what's the probability of randomly drawing a heart? (Hint: There are 13 hearts in a deck.)