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Overview

How much control do we really have over our lives? To what extent can we attribute our success to skills and abilities, rather than external factors such as luck or fate? Is it possible for us to predict future events, and if so, how?

This book explores the role of chance in our lives by looking at some statistics, reviewing history and mathematical concepts. It will equip you with a better understanding of how much your life might be based on chance.

You will learn about the stock market and how a man predicted it for 18 years. You will also learn why HIV tests can be less scary than you think, as well as how Galileo revolutionized scientific studies by rolling dice. Finally, you’ll read about Bruce Willis’s Hollywood success from 1984 and his vacation in Mexico.

Big Idea #1: The likelihood that an event will occur depends on the number of ways it can occur.

Do you think that winning a dice game depends on talent or luck? Probably luck, because we all know that it’s based on chance. However, if you’d won a dice game in the sixteenth century people would’ve thought that you had an exceptional throwing arm or were just lucky.

People didn’t know about probability until Galileo, who started observing and experimenting with random acts. For example, he would throw dice to study the probabilities of various outcomes.

Galileo explored the question of why three dice are more likely to total ten than nine.

A mathematician researched the question and came up with a scientific explanation. There are more possible combinations of numbers that add up to ten than there are for nine, so it is more likely to be chosen randomly (therefore it is not random).

Scientists such as Blaise Pascal would later expand on Galileo’s work. He also worked with dice and discovered something called the expectancy value. Imagine two people playing a game of dice where the first person to win ten rounds gets all the money, but if either player has eight wins when they have to stop, how much should each pay?

To figure out the probability of winning a game, you need to figure out all possible scenarios. In the case of blackjack, there are 16 possibilities. Then, look at how many ways each player can win in those scenarios (player one has 11 ways and player two has 5). The number of times that player one wins is divided by 16 (11/16), which is their expectancy value.

To determine whether or not an event will happen, you have to know the different ways it can occur. This is a fundamental idea in mathematics.

Big Idea #2: You can calculate the probability of certain outcomes using the law of large numbers.

If you were to roll a dice, would you expect the numbers to appear exactly once in six rolls? If they did, that would be quite random. However, it’s unlikely for that to happen. So what does this say about randomness?

In nature, there is no such thing as perfect randomness. One gambler named Joseph Jagger understood this in 1873 when he played Russian roulette. He found that some numbers came up more often than others on the wheel, and he won a lot of money based on his discovery. This poses an interesting question: If certain numbers appear again and again, what’s the probability they’ll continue to appear in the future? At the end of the seventeenth century, Jakob Bernoulli approached this question by studying it for twenty years before developing his golden theorem (also called law of large numbers). In order to understand it, imagine a jar with 5,000 pebbles; 60% are white and 40% are black. If you drew 100 pebbles from that jar, you might get 60 white ones or 40 black ones—or another combination that’s not too far off from those percentages.