How probabilities can help you

just started on this book after i finished my previous one..heh..about probabilities..seems interesting..heh..but i never knew probabilities could do this much in ur daily life..haha..but well..i dun think most people will go to the length of counting probabilities in their daily life cos some things are just too trivia or taken for granted..but nonetheless..some examples stated in the book are:

• you are planning a trip to a foreign country, but you are put off by reports of terrorst activities there. Should you go anyway? A simple understanding of probabilities will allow you to assess the risk of terrorism on your trip, and to decide whether the probabilities are high enough to affect your plans.
• You need a secret code to conduct a secure financial transaction over the Internet. If you just make up a code, an enemy agent might anticipate your psychology, guess the code, and obtain secret information. On the other hand, if u use randomness to generate your code, you can virtually guarantee security against even the cleverest enemy. modern computers use randomness in this way all the time.
• You are involved in a battle of wits with a clever opponent and want to avoid being outsmarted. You can use randomness to create a Nash equilibrium strategy in which your opponent can do no better than guess.
• The local police chief and politicians all insist that crime is out of control and that more money is needed for law enforcement. you can use linear regression to decide for yourself whether or not crime is really increasing.
• You are considering asking out that cute accountant in the business office, but you are worried that she will reject your advance or perhaps even complain about it. Utility theory allows you to quantify your feelings about your wants and fears, and to compute whether or not they justify making that phone call.
• you doctor informs you that you must take a certain drug, which is shown to be effective by the latest medicinal study. By considering the study’s biases and p-value, you can determine for yourself whether or not to accept its conclusions.
• A rival scoffs that you are more likely to be struck by lightning than to succeed in your business venture. A simple check of the numbers will reveal just how unlikely lightning deaths really are and put your rival’s comments into context.
• You are annoyed by all the spam e-mail you receive, and you wish to find a way to block it. Probability theory helps computers to separate spam from genuine messages, sparing you the burden of a jammed mailbox.
• In one day, you see three different people who have all dyed their hair green. Is this a new and popular fashion trend? Random events tend to occur in bunches due to Poisson clumping; many apparently striking coincidences or trends are the result of pure chances, and are of no meaning or consequence.
• A friend tries to stump you with “Monty Hall problem”: which of three doors is most likely to have a car behind it, if you already know that Door #3 is empty? the theory of conditional probability allows you to compute all the odds and make the right choice.
• you write a fantastic song, but you worry that perhaps someone else may have already written the exact same song. Probability theory provides a useful perspective on uniqueness and practically guarantees that your song is brand new.
• You wonder how scientists and engineers compute all the complicated quantities required to build bridges, conduct medical studies, and design nuclear reactors. Monte Carlo sampling uses randomness on high-speed computers to compute many such quantities.
• you  need to decide whether to call a poker bet or how many houses to buy in monopoly. Probability theory provides many insights into strategies fro games of chance, and using it allows you to win more often in the long run.

From [Struck by lightning-Jeffrey S. Rosenthal]

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