当前位置:考试网  > 试卷库  > 学历类  > 自考  > 自考公共课  >  发报台分别以概率0.6和0.4发出信号“1”和“0”。由于通讯系统受到干扰,当发出信号“1”时,收报台未必收到信号“1”,而是分别以概率0.8和0.2收到信号“1”和“0”;同时,当发出信号“0”时,收报台分别以概率0.9和0.1收到信号“0”和“1”。求(1)收报台收到信号“1”的概率;(2)当收报台收到信号“1”时,发报台确是发出信号“1”的概率。
试题预览

发报台分别以概率0.6和0.4发出信号“1”和“0”。由于通讯系统受到干扰,当发出信号“1”时,收报台未必收到信号“1”,而是分别以概率0.8和0.2收到信号“1”和“0”;同时,当发出信号“0”时,收报台分别以概率0.9和0.1收到信号“0”和“1”。求(1)收报台收到信号“1”的概率;(2)当收报台收到信号“1”时,发报台确是发出信号“1”的概率。

查看答案
收藏
纠错
正确答案:

设A1=“发出信号1”,A0=“发出信号0”,A=“收到信号1”

(1)由全概率公式,有P(A)=P(A|A1)P(A1)+P(A|A0)P(A0)=0.8x0.6+0.1x0.4=0.52

(2)由贝叶斯公式,有P(A1|A)=P(A|A1)P(A1)/P(A)=0.8x0.6/0.52=12/13

答案解析:

暂无解析

你可能感兴趣的试题

设A,B是n阶矩阵,记r(X)为矩阵X的秩,(X,Y)表示分块矩阵,则

设函数f(x)在点x0处具有二阶导数且f(x0)0,那末当f(x0)0时

一枚硬币连丢3次,观察正面H﹑反面T出现的情形.样本空间是:S=

下列诗歌中,被王国维称赞为“最得风人深致”的是()

《哭小弟》中引用了小弟的诗:“圆首悠悠无恨事,丹心一片向将来。”这两句所体现的小弟的美德是()

热门试题 更多>
试题分类: 计算机四级
练习次数:0次
试题分类: 初级(口语)
练习次数:0次
How shops can exploit people's herd mentality to increase sales 1.A TRIP to the supermarket may not seem like an exercise in psychological warfare—but it is.Shopkeepers know that filling a store with the aroma of freshly baked bread makes people feel hungry and persuades them to buy more food than they had intended.Stocking the most expensive products at eye level makes them sell faster than cheaper but less visible competitors.Now researchers are investigating how “swarm intelligence” (that is,how ants,bees or any social animal,including humans,behave in a crowd) can be used to influence what people buy. 2.At a recent conference on the simulation of adaptive behaviour in Rome,Zeeshan-ul-hassan Usmani,a computer scientist from the Florida Institute of Technology,described a new way to increase impulse buying using this phenomenon.Supermarkets already encourage shoppers to buy things they did not realise they wanted: for instance,by placing everyday items such as milk and eggs at the back of the store,forcing shoppers to walk past other tempting goods to reach them.Mr Usmani and Ronaldo Menezes,also of the Florida Institute of Technology,set out to enhance this tendency to buy more by playing on the herd instinct.The idea is that,if a certain product is seen to be popular,shoppers are likely to choose it too.The challenge is to keep customers informed about what others are buying. 3.Enter smart-cart technology.In Mr Usmani's supermarket every product has a radio frequency identification tag,a sort of barcode that uses radio waves to transmit information,and every trolley has a scanner that reads this information and relays it to a central computer.As a customer walks past a shelf of goods,a screen on the shelf tells him how many people currently in the shop have chosen that particular product.If the number is high,he is more likely to select it too. 4.Mr Usmani's “swarm-moves” model appeals to supermarkets because it increases sales without the need to give people discounts.And it gives shoppers the satisfaction of knowing that they bought the “right” product—that is,the one everyone else bought.The model has not yet been tested widely in the real world,mainly because radio frequency identification technology is new and has only been installed experimentally in some supermarkets.But Mr Usmani says that both Wal-Mart in America and Tesco in Britain are interested in his work,and testing will get under way in the spring. 5.Another recent study on the power of social influence indicates that sales could,indeed,be boosted in this way.Matthew Salganik of Columbia University in New York and his colleagues have described creating an artificial music market in which some 14,000 people downloaded previously unknown songs.The researchers found that when people could see the songs ranked by how many times they had been downloaded,they followed the crowd.When the songs were not ordered by rank,but the number of times they had been downloaded was displayed,the effect of social influence was still there but was less pronounced.People thus follow the herd when it is easy for them to do so. 6.In Japan a chain of convenience shops called RanKing RanQueen has been ordering its products according to sales data from department stores and research companies.The shops sell only the most popular items in each product category,and the rankings are updated weekly.Icosystem,a company in Cambridge,Massachusetts,also aims to exploit knowledge of social networking to improve sales. 7.And the psychology that works in physical stores is just as potent on the internet.Online retailers such as Amazon are adept at telling shoppers which products are popular with like-minded consumers.Even in the privacy of your home,you can still be part of the swarm. Questions 1-6 Complete the sentences below with words taken from the reading passage.Use NO MORE THAN THREE WORDS for each answer. 1.Shopowners realize that the smell of _______________ can increase sales of food products. 2.In shops,products shelved at a more visible level sell better even if they are more _______________. 3.According to Mr.Usmani,with the use of “swarm intelligence” phenomenon,a new method can be applied to encourage _______________. 4.On the way to everyday items at the back of the store,shoppers might be tempted to buy _______________. 5.If the number of buyers shown on the _______________ is high,other customers tend to follow them. 6.Using the “swarm-moves” model,shopowners do not have to give customers _______________ to increase sales.
试题分类: 阅读
练习次数:52次
试题分类: 口语
练习次数:0次
扫一扫,手机做题