The 12nd tell
The dried food takes notes
Hello, today is the 7th unit. We had listened to a mother to say to the child: "You had been not been how carefully again! " such word. But economist may say so to his mother: "Mom, you are actually likely too pursuit is safe. " today in this one unit, we can come dug economist is how to reach " excessive security " of this conclusion.
Actually you should can understand this conclusion backside roughly reason: If there is free lunch on the world, also do not have " free security " . Safety strengthens a minute, cost can raise one minute. Although did not produce cash cost, also affirm existence opportunity cost. Decrease ceaselessly and increase of limit cost of value ceaselessly as limit, in a certain node, addition security and addition cost appearance the loss outweights the gain than the likelihood. Be short of with information like breaking, can put in standard of standard of risk of a first-rate and first-rate safety.
How old does the safe ability of degree calculate excessive security? How old has the risk of degree just calculated little risk?
If we continue to hold to the Pareto law that has studied before us, so the safe value that our everybody can determine him. Can determine the mainest factor and rate for you without any any spectator, economist or someone else.
A certain place is gone before people drives every time, when perhaps crossing some pedestrian crosswalk, existence is contused or bump into dead risk, but the freewill choice that this is an individual. If we believe rational principle, we should prove, the value enough that heads for destination lets us assume corresponding risk.
Economist thinks, when considering public policy issue, we must perhaps must gift to human life some kind of value that can measure, gift at least value of some kind of statistic. E.g. : If we plan to establish a channel in a Shan Zhongxiu, very possible meeting produces casualty accidents in construction process, so we must judge such whether worth while doing.
I once also had offerred this point of view when university lecture, a student conveyed his crosscurrent particularly excitedly at that time. He says: "The person's life is impayable. " actually I think, what he says is his own life value. Nevertheless he demonstrated a kind of point of view really. I tell him: "I am not the life value that should determine you. Your life is impayable. " next I ask him: "You how do today come to the school? " he says: "I drive come. " the what car that I ask to he leaves again, he said brand of a car, one kind suits the small-sized and vintage car of student economy condition. Next I say with him: "You should take car of arms of an armor carry, you can buy from inside inventory of American legionary the rest. Such, you just are met safety is gotten much. You just are met safety is gotten much..
You think euqally with him for certain, feel I say too exaggeratively. Then, I say with him again: "To you, open an armor to carry arms car will reduce go to school the risk in road is obvious too exaggerative, look in me so, what you are spent to the heavy visual range of own life and imagine without you is tall in that way. What you are spent to the heavy visual range of own life and imagine without you is tall in that way..
After I say, everybody is silent. In fact, our behavior proves over and over: Occasionally, we think we took too safe safeguard really, when the cost that be being reduced especially or eliminates a risk is too high, can appear this kind of conclusion. Actually we can live in the space that closes completely or in subterranean bomb shelter, meet so more safe and macrobian.
But, fine long hair of this kind of life is insignificant. The price that we should pay is too big, include money not only, still include the chance of all and normal life that we must abandon. We special really the certain part in treasuring the life, can sacrifice even for them a bit safety. A lot of businesses that make the life significant are accompanying a risk. So, a lot of moment, you may have bit of excessive pursuit security.
Actually, safe problem is not the risk of mortality, or very serious body harm, this logic applies to all risks that we face in the life. E.g. : The car that you just buy may be put in blemish; You come 30 years all the time the fund of provide for the aged that capture expends may go bankrupt; You are cautious built house may be gobbled up by conflagration; Your professional choice may be very bad -- all these are the risks that we face.
How to accompany with risk photograph?
I had been told in the first unit, on this world, everything causes an effect possibly to other issue, certain result and influence we cannot foretell possibly forever. Do not have a person to be able to control the outcome of incident, nowhere is absent the risk. Us understandable, management and control them. But, we do not have ability, eradicate even without idea tentative idea risk. So, the problem that we face is: How to accompany with risk photograph? This is the subject that we discuss today.
When discussing this issue, economist can distinguish normally two things: One is uncertainty, another is a risk. The uncertainty that economist place says, it is to show the information that we possess is not quite complete, the problem of uncertainty can get settlement through possessing more and more significant information, such we can forecast future well and truly. If we possess complete, accurate information, can remove uncertainty, but try to master reason of dispute of all and significant information, need to pay high cost.
Today, what I should discuss with you is another element: Economist says for " risk " . We can obtain more and more information from certain place, but we still do not know we want what to know truly. We may think those who know is, a certain incident is met for certain in future happen.
Some incident are complete unknowable. For instance: If you use yourself,all moneys collect the influence data of cast coin, the data information such as reaction of bounce of the quality that includes coin, gyral force, wind speed, different lateral, no matter you gathered such how many information, you cannot agree to place the result of cast coin forever. If you try to forecast a result according to the mass data of chuck coin, so although you mastered all information, unsuccessful probability is remained 50% , this is so called random incident. Wanting to achieve determinism result is impossible, what this points to is " probable sex " , namely the probability incident that we often say. Probable sex depends on luck, and be put in the risk with inevitable move.
Answer a risk scientificly: "Expectation is worth " concept
What be faced with when us is decision-making when involving this kind of risk, how should be answered scientificly? Face probable sex decision-making, economist can be used normally " expectation is worth " concept of this kind of formalization. Economist knows, life is not electronic game, nonexistent " come again " option, without the opportunity that has come afresh. When we face a risk, try over and over impossibly ceaselessly.
And expectation value, tell from the concept, it is to if we can try over and over,show those who differ is decision-making, after ceaseless attempt we can get what kind of result. If we are OK and new decision-making, experience over and over, the decision-making result that evaluates every time, so how are these decision-making average effects met? Is average result met how?
[knowledge is little play a window]
Expectation is worth (Expected Value) : Show random experiment issues what the result calculation that repeats for many times goes out to be equal in equal opportunity " expectation " average.
How to expect to be worth certainly:
1. your need knows the probability of every kinds of potential outcome;
2. is multiplied with the value of the result with probability;
3. general each product sue for peace.
We practice now. Above all, what we should do is: Understand " probability " what is official mathematical definition. For formal ground, the probability of any incident, for instance on morning of cast coin word, the probability that throws dice to must be waited a moment at 3 o'clock, it is the business of the earning after some kind of potential outcome divides the number with all and potential outcome.
Toss a coin, how many kinds of possibility can you get? Have two kinds apparently: One kind is word morning go up, one kind is to spend face to go up, getting part with beautiful upturned possibility on word morning so is be 1/2 or 0.5. If throw a dice, get a medium kind 3 o'clock is 6 kinds of possibility. So, obtaining the probability 3 o'clock is 1/6, perhaps say probability is 0.1667. If I throw this dice ceaselessly, I am very OK believe firmly the ground says, appear the average opportunity 3 o'clock is 1/6 about. But, I cannot agree to place cast when to can get. Once I knew probability, and can value of accurate estimation result, so I can be calculated expectation value.
We will play " toss coin " game -- " I win the word, spend you to win " . Game is regular 1:
You toss a coin;
If on word morning, you give me 1 dollar;
If spend face to go up, you give me 0.5 dollars.
My average income and your average pay is 0.75 dollars.
If you toss this coin ceaselessly, have half the time so I can get 1 dollar, half the time gets 0.5 dollars. But, you toss this coin every time, my average income and your average pay is 0.75 dollars. Nevertheless, when any cast, won't appear of 0.75 dollars trade the forehead, it is the average that produces actually only. It is very important that I feel to understand this. But, you are not willing to play this game with me for certain, because understand expectation value what to do not have possibly to your decision,affect, you do not need to apply sophisticated mathematical reasoning to be able to know, this game always is you are defeated.
So I am adjusted simply, those who raise sport is practical. Game is regular 2:
You toss a coin;
If on word morning, you give me 1 dollar, I give you 0.8 dollars;
If spend face to go up, you give me 0.5 dollars, I give you 0.8 dollars.
Your average income is 0.05 dollars.
Every time cast coin, you can get 0.8 dollars. How much is expectation value? After be being calculated for many times, how much is your average loss? Will on average look, you can beat 0.05 dollars.
Game is regular 3:
You toss a coin;
If on word morning, you give me 1 dollar, I give you 0.7 dollars;
If spend face to go up, you give me 0.5 dollars, I give you 0.7 dollars.
Your average loss is 0.05 dollars.
If I say, "In game process, every cast, I pay 0.7 dollars to you " . So for many times after cast, your average loss is 0.05 dollars.
Understanding expects to be worth, what can help you make reason below circumstances of this kind of risk is decision-making. Gambling house special make money, depend on gambling house operator special be good at computation expecting to be worth. A lot of layers and backers can be inside cutty time the capital of play away your writing, because they do not know how to be calculated,expect to be worth namely, or they believe probability to be able to produce an effect to them far from.
Schoolbook likes to use very much throw coin, dice or take out a piece of A to serve as the example that explains probability from inside a pair of card, because people decides their objective probability very easily. Actually in actual life, also have a few objective probability that decide easily.
Cite a case: In the city that I live, differ in thousands ways of rich colour bonus, a few websites forecast all sorts of probability that play a way technically:
In the lottery that every 135 million pieces of prices are 1 dollar, can appear the large award of a 1.75 million dollar.
So, the expectation value of every pieces of lottery is 0.06 dollars, namely people anticipates redound with what 1 dollar got 0.06 dollars.
Those who blow happy lottery is blow to play a way here about the same also, the way plays in some in:
The probability that acquires stake of 20 thousand dollar is 1/1000000.
So, your expectation value is 0.02 dollars about.
A piece of any lottery won't pay 0.02 dollars, the organizer is right 999, a single cent or penny of 999 pieces of lottery does not pay, just pay 20 thousand dollar to a piece of lottery. Every buy colour civilian a piece of lottery, gotten expectation value is 0.02 dollars.
I had seen end of a car sticks advertisement to say: "Rich colour is the way of a kind of pay taxes that for maths bad person devises (The Lottery Is A Tax On People Who Are Bad At Math. ) . " in suffer among the American that visit, the person that has 1/4 thinks, rich colour win a prize in a lottery is a kind of when realize economic safeguard feasible method. These people may not be very geographical sex; They just may lack enough information.
The uncertainty of the risk
In our life, existing a lot of more more complex than throwing coin or dice cases. In the numerous life risk that faces in us, still a few do not have the objective probability that limits adequately, perhaps say to do not have the objective probability that can limit easily. Every every incident, participator and every kinds of circumstance, put in certain difference with other case.
I think those who know is: How much is the probability that my home building catchs fire? My home car by the probability of pilfer how much be? How much is the probability that I need to set a false tooth? How much is the probability that next year I need hospitalization? For computation these probability, I cannot be counted on simply will calculate with the method that throws dice to win A medal so that check the number perhaps smokes playing cards. We need to use historical data to undertake estimation. But, I am informed: Can be these probability used on my body directly? Is prospective probability mixed same in the past? Rely on not to rely on chart after all quite so?
Cite a case again: Inside American any year, because hurricane brings about a countryman,dead risk is about 6 million 1/0. But, I believe firmly, if my life is in the area with higher height above sea level, risk probability is met lesser; If I live in altitude the area under sea level, the circumstance can compare how terrible. If I want to know fire sends the probability that the person dies, such I am OK calculating: American fire dead number is removed with population number, the average probability that reach is about 91, 000 1/0. But if I am mixed,a person that smoke lives together, this kind of probability can rise; If I installed fire control warning apparatus, this kind of probability can drop.
Mathematician can tell us for certain, how much is the victorious probability of game of an elaborate design. I hope, we also decide easily to the true probability of incident is concerned in real life. But regretful is, probability and risk are put in uncertainty. We can decide the true probability of probable sex risk without enough information, the actual application that so expectation is worth can become more difficult.
