What is the probability?
Probability is a way of thinking about situations where outcomes of our actions are uncertain, or the outcomes of some events are uncertain. For example, today I check the weather forecast and the forecast was that there’s a 5% chance of rain. Given it’s only 5% chance I thought well what does it mean 5%? Well 5% means that out of hundred days I should expect about five of them to actually be raining. Given it was only 5% I decided not to take my umbrella and it turns out to be a good decision.
In general probability is used a lot of in science in trying to detect patterns in data in what we observe. Weather is a one example trying to predict waves for surfers. So that they can come on a good day to the beach for a good swell, that’s another good example of trying to predict from patterns in one part of the earth. What am I going to see in on my beach tomorrow?
Probability is used sports
You can think for example about a basketball player who has different probability of making a shot depending on where he stands on the cards. A good example of thinking about it is a decision whether to take a 3-point shot or a two-point shot walking closer to the basket.
Probability doesn’t allow us to predict well
Think about tossing a coin, when you toss a coin we would say there’s probability 1/2 or 50% they will come out tails, and 50% or 1/2 they will come up heads. We can assign probabilities, but that doesn’t really help us guess whether it will be heads or tails. Take a coin and throw it, and see whether it comes up heads or tails. Suppose it comes heads, throw the coin second time, and see whether it comes up heads or tails. Suppose it comes up heads the second time.
Now think about throwing the third time. Do you think it is more likely for the third time it will come up heads or tails?
Probabilities are around us all the time and as a result, people form a lot of intuitions about probabilities. At the same time to make successful decisions, often understanding some probability theories can make even better decisions.
Probability is used in various fields
Spaceship
You can think about engineers trying to build a spaceship to send it to Mars. It’s not that they want to send a thousand of them, and learn trial and error which ways work. They would like to be able to compute things ahead of time – to send the spaceship to Mars, so it hits the first time. Doesn’t always work, but we try to minimize the chances we will miss the planet.
Make predictions about weather
There are a lot of examples of situations where experts make decisions for us. There are people whose job is to make predictions about weather, especially for companies whose business depends very much on weather. Think about a manager of a power plant who has to predict whether the electricity will be needed or not. That very much depends on how much wind there is.
Investment
Another field in which there’s a lot of people who work on trying to predict outcomes. And the calculate probabilities of certain outcomes is finance. More people working in banks whose job is to pick companies to invest in, and the decision where to invest or not, depends on their estimates of probabilities whether certain inventions will be profitable or not.
You may wonder whether there is still a lot of areas in science where we are trying to compute probabilities, that we are far from knowing what the patterns are, that would give us probabilities. A good example of that would be weather. While weather forecasts for the next day are fairly accurate if you think about weather forecasts for a week from today, they tend to be very inaccurate, another great area that we would love to have better probabilities to predict batteries earthquakes. Now we still don’t have good ways of predicting when earthquakes and where would they appear.
The third thing could be curing cancer we would like to have better models that predict which kinds of cures work for which particular cancer. We would like to invite you now to your lesson to learn more about probabilities. And there is a hope that if you learn it, and you decide you like it, you can become a scientist and create great discoveries for us all.
