Quotes About Probability

The human mind tends to estimate the probability of an event from the ease with which it can recall examples, and scenes of carnage are more likely to be beamed into our homes and burned into our memories than footage of people dying of old age.1 No matter how small the percentage of violent deaths may be, in absolute numbers there will always be enough of them to fill the evening news, so people's impressions of violence will be disconnected from the actual proportions.

The nature of news is likely to distort people's view of the world because of a mental bug that the psychologists Amos Tversky and Daniel Kahneman called the Availability heuristic: people estimate the probability of an event or the frequency of a kind of thing by the ease with which instances come to mind.11

And as excellent as our cognitive systems are, in the modern world we must know when to discount them and turn our reasoning over to instruments—the tools of logic, probability, and critical thinking that extend our powers of reason beyond what nature gave us.

Third, don't confuse an anecdote or a personal experience with the state of the world. Just because something happened to you, or you read about it in the paper or on the Internet this morning, it doesn't mean it is a trend. In a world of seven billion people, just about anything will happen to someone somewhere, and it's the highly unusual events that will be selected for the news or passed along to friends. An

The human mind tends to estimate the probability of an event from the ease with which it can recall examples, and scenes of carnage are more likely to be beamed into our homes and burned into our memories than footage of people dying of old age.

The cluster illusion, like other post hoc fallacies in probability, is the source of many superstitions: that bad things happen in threes, people are born under a bad sign, or an annus horribilis means the world is falling apart. When a series of plagues is visited upon us, it does not mean there is a God who is punishing us for our sins or testing our faith. It means there is not a God who is spacing them apart.

People are surprised to learn that if 23 people are in a room, the chances that two will share a birthday are better than even. With 57 in the room, the odds rise to 99 percent. Though it's unlikely that anyone in the room will share my birthday, we're not looking for matches with me, or with anyone else singled out a priori. We're counting matches post hoc, and there are 366 ways for a match to occur.

The asymmetry has been confirmed in the lab by showing that people will take a bigger gamble to avoid a sure loss than to improve on a sure gain

Finally, power-law distributions have "thick tails," meaning that they have a nonnegligible number of extreme values. You will never meet a 20-foot man, or see a car driving down the freeway at 500 miles per hour. But you could conceivably come across a city of 14 million, or a book that was on the bestseller list for 10 years, or a moon crater big enough to see from the earth with the naked eye—or a war that killed 55 million people.

This cognitive illusion was first noted in 1968 by the mathematician William Feller in his classic textbook on probability: "To the untrained eye, randomness appears as regularity or tendency to cluster."33 Here are a few examples of the cluster illusion. The

New information reduces our ignorance and changes the probability. If that sounds mystical or paradoxical, think about the probability that a coin I just flipped landed heads. For you, it's .5. For me, it's 1 (I peeked). Same event, different knowledge, different probability.

Intuitive probability is driven by imaginability: the easier something is to visualize, the likelier it seems. This entraps us into what Tversky and Kahneman call the conjunction fallacy, in which a conjunction is more intuitively probable than either of its elements.

The writer Warwick Cairns calculated that if you wanted your child to be kidnapped and held overnight by a stranger, you'd have to leave the child outside and unattended for 750,000 years.211

descuido de la probabilidad».

according to the transition probabilities of English. Remember Chomsky's sentence Colorless green ideas sleep furiously. He contrived it not only to show that nonsense can be grammatical but also to show that improbable word sequences can be grammatical. In English texts the probability that the word colorless is followed by the word green is surely zero. So is the probability that green is followed by ideas, ideas by sleep, and sleep by furiously.

That bias is built in because of the asymmetry of time: there is a nonzero probability at any moment that we will be felled by an unpreventable accident like a lightning strike or landslide, making the advantage of any costly longevity gene moot.

The nature of news is likely to distort people's view of the world because of a mental bug that the psychologists Amos Tversky and Daniel Kahneman called the Availability heuristic: people estimate the probability of an event or the frequency of a kind of thing by the ease with which instances come to mind.

The press is an availability machine. It serves up anecdotes which feed our impression of what's common in a way that is guaranteed to mislead. Since news is what happens, not what doesn't happen, the denominator in the fraction corresponding to the true probability of an event—all the opportunities for the event to occur, including those in which it doesn't—is invisible, leaving us in the dark about how prevalent something really is.

Probabilites are not about the world; they're about our ignorance of the world.

With a constant probability of ending every year, a war is most likely to end after its first year, slightly less likely to end within two years, a bit less likely to stretch on to three, and so on.

Nothing is impossible. Some things are just less likely than others.

The more you open yourself up to the possibility that good things will happen the higher probability is that good things will in fact happen.

Improbable things happen a lot.

if gambling is exciting, you're doing it wrong.