# What is Probability? How Does It Shape Our Lives?

Article Summary: Have you ever heard your parents or other adults wishing that they could win millions of dollars in the state lottery? Experts say that a person has the same chance of winning the lottery as the chance of being struck by lightening! Only a few people are hit by lightening just as only a few people win the multi-million dollar prize in the lottery.

Have you ever heard your parents or other adults wishing that they could win millions of dollars in the state lottery? Experts say that a person has the same chance of winning the lottery as the chance of being struck by lightening! Only a few people are hit by lightening just as only a few people win the multi-million dollar prize in the lottery. These are two examples of probability and two examples of very unlikely events. An unlikely event is one that probably won't happen. See how close the word "probably" (which you already know) is to "probability"?

Let's pretend that you are taking a walk in the park along a paved trail and you reach a fork in the path. You can take the path on the left side or you can take the path on the right side. It's up to you to decide and you don't know what is ahead in either direction. You have no preference as to which way to turn. Then we could say that you have an equal chance of turning left or turning right. This means that the probability, or chance, of turning left or turning right are the same because there is nothing to influence the choice.

Let's skip ahead to your senior year in high school when you are ready to go to college. You like two schools with about the same costs to attend. You receive a scholarship for \$10,000 to attend one of the schools and no scholarship from the other. What is the probability of attending each school? It is very likely that you will attend the school that offered you the scholarship. Then the probability of attending that school is higher than attending the school without the scholarship.

Probability is all around us and it does influence our lives every day. Before the measles vaccine was invented, most children became sick with measles when they were in elementary school. Back then the probability of getting measles was high. Since so many children would get sick, researchers decided to look for a vaccine. Now if children get vaccinated for measles, the probability of getting measles is very low. Working at preventing diseases that have a high probability of making people sick is one example of how probability influences lives.

Weather forecasts are another way we use probability every day. Do you ever see the forecast that says 80% chance of showers for tomorrow? That means that in the past, 8 days out of 10 that had weather like today were followed by showers. That's a high probability and you had better bring your umbrella.

What do you think the highest probability is? Is that something you can figure out? Probably! The highest probability is 100% which means the event will happen for sure. Sometimes the weather forecast is simply it will rain tomorrow and it does. Sometimes such a great storm is coming that the weather forecaster can say for sure that it will rain, there is a 100% chance of rain.

What is the lowest probability? The lowest probability is 0%, there is no chance of the event happening. If you are grounded, what is the probability of going to the basketball game? Most likely 0%.

Human beings make decisions all the time; sometimes the decisions are simple and other times they are complicated and change the rest of our lives. Everyone who thinks and plans for their future uses probability - deciding what are the chances of - in the planning process.

Can you think of some ways that probability has changed your decisions?