The term probability refers to the likelihood of an event occurring. Probability can be expressed in a variety of ways including a mathematically formal way such as using percentages. It can also be expressed using vocabulary such as “unlikely,” “likely,” “certain,” or “possible.”

## Ways to Express Likelihood of Occurrence

Some examples of probability include:

• There is a 20 percent chance of rain tomorrow.
• Based on how poorly the interview went, it is unlikely I will get the job.
• Since it is 90 degrees outside, it is impossible it will snow.
• After flipping this coin 10 times and having it land on heads 8 times, the probability of landing on heads is still 50 percent. The odds stay the same regardless of what it landed on before or after the 11th flip of the coin.
• On a spinner that has four colors occupying equally sized spaces, there is a one in four probability it will land on any one color.
• In a drawer of ten socks, 8 of them yellow, there is a twenty percent chance of choosing a sock that is not yellow.
• Since it is sunny and hot, it is very likely I will go to the pool today.
• There is a 50 percent chance of snow tonight.
• Because the ground is warm, it is very unlikely that the snow will stick to the ground.
• There is a foot of snow on the ground; so, it is extremely likely school will not be in session tomorrow.
• She did not pay her mortgage payment three months in a row; so, it is possible her house will be foreclosed upon.
• That employee was rated “Employee of the Month” three times last year; so, it is very likely she will receive a good evaluation.
• Our team has won all of our football games this season; so, it is likely we will defeat the worst team in the league when we play against them.
• She comes to work late nearly everyday; so, it is likely she is going to be reprimanded.
• There are one hundred cars on the sales lot that are silver. The probability of a customer choosing a silver car is 50%.
• The probability of winning the lottery is one in many millions.
• There are nine red candies in a bag and one blue candy in the same bag. The chances of picking the blue candy are 10%.
• In my closet are five pairs of shoes, four of which are black. The chances of picking a black pair of shoes is 4 out of 5.
• Since I am not feeling well, it is very unlikely I will be going to a party tonight.
• Given that she calls out of work once a week, it is quite possible that she will do so again this week.
• Since it is supposed to rain tomorrow, it is very likely I will need to use my windshield wipers when I go to work.
• Because his dog barks every time the postal carrier comes to the house, it is very likely the dog will do so today.

Now you can see how probability works and these examples help to illustrate different ways to express probability.