未知题型 某冶金工作者对锰的溶化点作了4次试验,结果分别为(单位:℃)1 269、1 271、1 263、1 265,假定数据服从正态分布,在α=0.05条件下,试检验: ①该工作者对锰溶化点的测量的平均结果是否符合于公布的数字1 260℃; ②侧量结果的标准差是否大于2℃.
单项选择题 根据短文回答 31~35 题。 Characteristics of PublicityPublicity offers several benefits.There are no costs for message time or space。An ad in prime-time television may cost$250.000 to$500.000 0r more per minute。whereas a five-minute report on a network newscast would not cost anything.However, there are costs for news releases,a publicity department,and other items.As with advertising,publicity reaches a mass audience.Within a short time。new products or company policies are widely known.Credibility about messages is high,because they are reported in independent media.A newspaper review of a movie has more believability than an ad in the same paper, because the reader associates independence with objectivity Similarly, people are more Likely to pay attention to news reports than to ads.For example.The Women's Wear Daily has both fashion reports and advertisements.Readers spend time reading the stories,but they flip through(浏览)the ads.Furthermore,there may be l o commercials during a half-hour television program or hundreds of ads in a magazine.Feature stories are much fewer in number and stand out clearly.Publicity also has some significant limitations.A firm has little control.over messages,their timin9,their placement,or their coverage by a given medium.It may issue detailed news releases and find only portions cited by the media;and media have the ability to be much more critical than a company would like.For example in l 982。Procter Gamble faced a substantial publicity problem over the meaning of its 123-year-old company logo(标志).A few ministers and other private citizens believed that the symbol was sacrilegious(亵渎的).These beliefs were covered extensively by the media and resulted in the firm receiving 1 5.000 phone calls about the rumor in June alone.To combat this negative publicity, the firm issued news releases featuring prominent clergy(神父)that refuted(消除)the tumors,threatened to sue(控告)those people spreading the stories,and had a spokesperson appear on Good Morning America.The media cooperated with the company and the false rumors were temporarily put to rest.However, in l 985。negative publicity became so disruptive that Procter& Gamble decided to remove the logo from its products.A firm may want publicity during certain periods.Such as when a new product is introduced or new store opened。but the media may not cover the introduction or opening until after the time it would aid the firm.Similarly, the media determine the placement of a story:it may follows a report on crime or sports.Finally, the media determine whether to cover a story at all and the amount of coverage to be devoted to it.A company-sponsored jobs program might go unreported or receive three-sentence coverage in a local newspaper. 第 31 题 The word 'mass'in Line 5 could best be replaced by( ).A.grouped.B.crowded.C.gathered.D.large.
单项选择题 根据下列文章,请回答 36~40 题。 Recycling Around the World Recycling is one of the best environmental success stories of the late 20th century.But we could do more. People must not see recycling as fashionable, but essential.The Japanese are very good at recycling because they live in a crowded country. They do not have much space. They do not want to share their limited space with rubbish. But even so, Tokyo area alone is estimated to have three million tons of leftover rubbish at present.In 1996, the United States recycled and composted (制成肥料) 57 million tons of waste (27% of the nation's solid waste). This is 57 million tons of waste which did not go into landfills and incinerators (焚化炉). In doing this, 7,000 rubbish collection programmes and recycling centres helped the authorities.In Rockford, a city in Illinois, US, its officials choose one house each week and check its garbage (废物). If the garbage does not contain any newspapers or aluminium (铝) cans, then the resident of the house gets a prize of at least $1,000.In Japan, certain cities give children weekly supplies of tissue paper and toilet paper in exchange for a weekly collection of newspapers.In one year Britain recycles:· 1 out of every 3 newspapers.· 1 out of every 4 glass bottles and jars(罐子).· 1 out of every 4 items of clothing.· 1 out of every 3 aluminium drink cans.In l 999 Hong Kong transported l.3 million tons of waste to mainland China for recycling.Around 535,000 tons of waste were recycled in Hong Kong itself.Over half the things we throw away could be recycled.That means we could recycle 10 times as much as we do now.However,recycling needs a lot of organisation and special equipment.Also,there is not much use for some recycled material. 第 36 题 Which of the following is NOT true of the Japanese?A.They have recycled all their waste.B.They live in a crowded country.C.They are very good at recycling.D.They have to share their limited space with rubbish.