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What is probability? -

Probability is a term used in mathematics to describe the likelihood of something happening. Using math, we can predict the odds, and this is what probability does.

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How is probability calculated? -

Probability is calculated in terms of percentages and fractions. Here are a few examples of how these are calculated and described.

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It’s certain -

This is when there is a 100% probability of something happening. It’s the highest possible likelihood.

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It’s likely -

When it’s “likely” that something will happen, this means that there is a 50% to 100% probability of it happening.

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There’s an even chance -

This one is used to describe the exact middle. Meaning that there is a 50% chance of it happening or not happening.

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It’s unlikely -

When something is unlikely to happen, it is because it has less than 50% probability.

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It’s impossible -

Opposite to the “it’s certain,” this is when there is zero likelihood of something happening.

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Types of probability -

Now that we’ve looked at how probability is calculated, it’s also important to understand the types of probability and what they mean.

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Classical probability -

A basic example of classical probability is flipping a coin. All possible outcomes that action can lead to are recorded and then a probability is calculated. E.g. flip a coin 20 times and measure the results 20 times.

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Experimental probability -

This is calculated using the number of total possible outcomes by the total possible number of trials. E.g. tossing a coin only has two possible outcomes: heads or tails. If you flip the coin 20 times and it lands on heads eight times, then the experimental probability is 8/20.

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Theoretical probability -

This is about “the number of favorable outcomes divided by the total number of possible outcomes.” E.g. a die has six sides, which means six different possible outcomes. So there is a one in six chance of the die landing on #4 (or any other number).

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Subjective probability -

Subjective probability is based upon subjective elements such as feelings or emotions. E.g. betting on a sports team just because it’s a person’s favorite team.

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Probability in real life -

Now, let's take a look at how these concepts apply in real life.

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Weather forecast -

As you have probably noticed, most forecasters mention probabilities. For instance, if there is a 65% chance of rain, you are more likely to take an umbrella with you.

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Weather forecast -

But as you have also probably noticed, sometimes the prediction is wrong. The forecast is done using a wide range of data, including historical records, current trends, etc. So, that 65% chance of rain was calculated based on days with similar weather conditions.

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Sports outcomes -

Many coaches decide on the strategy and tactics for games based on probability. The teams, players, where the game will take place, etc., will often dictate the end result.

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Autocorrect software -

This is one most of us experience daily. Word suggestions as we type on our smartphones are calculated based on probability (e.g. how commonly used is one word after another).

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Games of chance -

A good example would be a card game. Probability (as well as statistics) play a role in how the game will develop and what are the chances of winning it.

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Insurance -

Insurance is vastly based on probability. For example, the chances of getting into a car accident increases as soon as you sit behind the wheel. If you were 100% certain you would never have an accident, you wouldn't need insurance, right?

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Insurance -

A clear example of how probability is employed, is by how much premium a client pays. Usually age, gender, and other factors play a role in the likelihood of the driver getting into an accident, and insurers know this.

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Traffic lights -

Traffic signs are programmed according to the number of vehicles that are likely to circulate on a given road and influence traffic flow. How fast you can drive through a road with several traffic lights can be calculated using probability.

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Election results -

The prediction of election results is made using a number of indicators, namely the historical records of how a region has voted in the past. Then exit polls and trends are added into the mix and a winning/loss probability is calculated.

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Lottery -

There is one way you can ensure you win the lottery: by buying every single ticket! In reality, you will have to rely on probability to believe you have a chance of winning it.

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Lottery -

Basically, each time you play the lottery, you have a chance of winning it. But then, the likelihood is calculated depending on how many tickets are sold. So, even though you have a low probability of winning the lottery, it is still higher than if you didn’t play at all.

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Shopping -

Shopping suggestions use probability to target consumers with products they are more likely to buy. Shopping habits can be calculated using probability. For example, if you buy maternity wear off Amazon, it’s likely that a few months later you will get shopping recommendations for baby clothes.

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Stock market -

The stock market relies on a number of analytics to calculate the probability of stocks going up or down in price. Though sometimes, simple things can increase the probability of share prices falling. For instance, if a CEO says/does something controversial, it is likely that the company’s stock price will fall.

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Sales forecasting -

Companies predict future sales based on probability, and this is how they ensure they have enough stock. E.g. a florist will likely see a spike in sales on Valentine’s Day.

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Staffing -

How many people are working at a given place sometimes varies depending on probability. For instance, this often happens in grocery stores. If there is a probability that at a given day and time there are x amount of customers coming through the door, then they should be prepared.

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Natural disasters -

The probability of a natural disaster to occur at a particular place and time can also be calculated, based on historical records and other factors.

See also: 30 simple ways to increase your intelligence

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