An Introduction to Probability

Intro to Probability

Hi and welcome to this video tutorial on probability problems.

Simple probability problems can often feel intimidating, but they don’t have to be.
Let’s talk about the basic rules in probability and then try a practice problem. The most basic way to explain probability is using a division problem, where the number of desirable outcomes is divided by the number of all possible outcomes. Number of desirable outcomes divided by the number of all possible outcomes. For example, there are 5 red houses and 3 blue houses in this little cup, giving us a total of 8.

Let’s say I want a blue house when I randomly draw one out of the cup. Since there are 3 blue houses, that will go on top in our division problem, and since there is a total of 8 houses from which I can draw, the 8 goes on the bottom, giving us, the number of desirable outcomes divided by possible outcomes.

If, however, I take this red house out, the total number of possibilities has changed, and so has the probability of getting what I want. So let’s take out this house, now the total number of possible options is only 7, not 8, and there are still 3 blue houses, so that means I now have a 3 in 7 probability of get what I want.

I hope that helps, thanks for watching this video tutorial.



by Mometrix Test Preparation | Last Updated: May 8, 2019