Probability

Probability. The measure of how likely an event is to happen. From how likely it is for you to pick the yellow marble, to what number the spinner will land on, to what color shirt I am probably going to wear tomorrow, probability is everywhere. Unlike most other objectives you learn in math, probability can be used in everyday activities. - - - - - - - - - Just a few definitions to start us off on the same page: Event – One or more outcomes of an experiment. Outcome – The result of a single trail in an experiment. Sample Space - The set of all possible values that could happen in a given event - - - - - - - - - Let’s start off with an easy question, just to get your mind going. Jon just bought a one dollar bag of five cent candy from the Tiger’s Den. The bag includes 10 red, 3 white, 8 blue and 4 green candies. If he pulls out one candy from the bag without looking, what is the probability it will be red?

I would figure this question out by totaling the total candies there were and then how many candies were red. I would put the total number of candies as the denominator and the total amount of red candies as the numerator.

__10__ ßRed candies (NUMERATOR) 25 ßTotal candies (DENOMINATOR) The chance that Jon will pull out a red candy is 10 out of 25, which is 40 percent. - - - - - - - - - Now that we know how to do a simple question lets move on to a harder one: A drawer contains 10 red socks, 4 white socks, and 10 blue socks. Without looking you draw out a sock, return it, and draw out a second sock. What is the probability that the first sock is blue and the second sock is white?

I would figure out this question by again by finding the total socks. It would be 24. So for the first draw, a blue sock, the probability would be 10 out of 24. Since you are returning the sock to the drawer, the second draw for a white sock would be 4 out of 24. To find out the probability of getting a blue and then a white sock we would have to multiply the fractions together.

__10__ (For the Blue Sock) 24

Multiplied by…

__4__ (For the White Sock) 24

Equals… __40__ 576

In lowest terms this answer would be 5/72 (Just divide the top and the bottom by the same number to reduce fractions) So the chance that you would pull out a blue and then white sock from a drawer of socks is 5/72.

I hope this little blurb will help you understand somewhat how probability works. You can also research it on the internet or read our classroom blog, which is posted daily. I have included a website that I found very helpful in creating this WIKI.

[|www.mathgoodies.com/lessons/vol6/intro_**probability**.html]