 # How Probability Is Used in Real Life

Probability is the basis of statistics, and is very present in everyday life. Understanding probability becomes very important when you read newspapers and watch the news. There is often talk of probability and likelihood in society and in political matters. You may have noticed that you are talking about probability in discussions with friends and family.

In probability theory you divide the types of events into two groups. The first group is the events that we can calculate the probability of, the random events. An event is random when you do not know what is going to happen beforehand. Examples of random events are: Who will win the football match? What’s the chance of the US qualifying for the soccer tournament at the Summer Olympics? Will I get my numbers drawn in the lottery?

The second group contains the events that you cannot calculate the probability of. These events are called deterministic events. An event is deterministic when you know what is going to happen beforehand. An example of this type of event is whether the Earth orbits the Sun. It makes no sense to talk about the probability of whether the Earth will orbit the Sun tomorrow as well. We know this is going to happen. It is predetermined.

Theory

Probability is measured by a number between

0 and 1.

Converted into percentages, the probability is a number between

$0$ % and $100$ %.

There’s a $0$ % chance of something happening if it’s absolutely certain that it will not happen. An example of this is the probability of living forever. There is $0$ % probability that you will live forever.

There’s a $100$ % chance of something happening if it’s absolutely certain that it will happen. An example of this is the probability of dying. There is a $100$ % probability that you will die one day.

You can often hear people say

“It’s $\text{}110\text{}\phantom{\rule{0.17em}{0ex}}\text{%}$ certain”

or

“I gave it $\text{}120\text{}\phantom{\rule{0.17em}{0ex}}\text{%}$”.

Why is this wrong?

Since $100$ % is absolutely everything, you can’t be more sure than completely sure. It’s the same with effort. You can not give more than all the effort you have in your body. All of your effort is $100$ %, so it is not possible to give more than that.

The reason we still say this in everyday speech is that we want to emphasize that we really mean what we say, or that we have truly given all we have. It is simply a way we exaggerate to reassure those we talk to.