The key feature of an oligopolistic market is that a. each firm produces a different produ

A statistical analysis that combines information from several studies is called a meta analysis. A meta analysis compared aspirin with placebo on incidence of heart attack and of stroke, separately for men and for women (J. Am. Med. Assoc., 295: 306–313, 2006). For the Women’s Health Study, heart attacks were reported for 198 of 19,934 taking aspirin and for 193 of 19,942 taking placebo. a. Construct the 2×2 table that cross classi?es the treatment (aspirin, placebo) with whether a heart attack was reported (yes, no). b. Estimate the odds ratio. Interpret. c. Find a 95% con?dence interval for the population odds ratio for women. Interpret.(Asof2006,results suggested that for women, aspirin was helpful for reducing risk of stroke but not necessarily risk of heart attack.)

I. Read the following 6 short passages, and do the True and False based on each passage. 1. Physical proximity is important mainly in relation to intimacy and dominance. The normal degree of proximity varies between cultures and every species of animal has its characteristic social distance. 2. Orientation signals interpersonal attitudes. If person A is sitting at a table, B can sit in several different places. If he is told that the situation is cooperative he will probably sit at next to A; if he is told he is to compete, negotiate, sell something or interview A, he will sit opposite A; if he is told to have a discussion or conversation he usually chooses across the corner 3. Head-nods are a rather special kind of gesture, and have two distinctive roles. They act as reinforcers, i.e. they reward and encourage what has gone before, and can be used to make another talk more, for example. 4. Appearance. Many aspects of personal appearance are under voluntary control, and a great deal of effort is put into controlling them - clothes, hair and skin; other aspects can be modified to some extent by clothes and plastic surgery. 5. Non-linguistic aspects of speech. The same words may be said in quite different ways, conveying different emotional expressions, and even different meanings, as when “yes” is used as a polite way of saying “no”. (From a book by Michael Argyle titled The Psychology of Interpersonal Behaviour. It was published in London by Pelican in 1967 and this extract was from pages 36-37.) 1. ____ Physical proximity is important mainly in relation to intimacy and dominance.

Which kind of advertising is the following statement about? A. Broadcast Advertising B. In-store Advertising C. Print Advertising D. Celebrity Advertising E. Outdoor Advertising F. Public Service Advertising G. Online Advertising H. Give-a-ways Advertising 6. The internet platform changed the way products and services are advertised. Web advertisers spend big money on video ads, streaming banners and pop-ups to lure internet users to their company websites. Internet users are always bombarded with products and incentives.

7. Biodiversity of Australia Although most of Australia is semi-arid or desert, the continent includes a diverse range of habitats from alpine heaths to tropical rainforests. Fungi typify that diversity[clarification needed]; an estimated 250,000 species—of which only 5% have been described—occur in Australia. Because of the continent's great age, extremely variable weather patterns, and long-term geographic isolation, much of Australia's biota is unique. About 85% of flowering plants, 84% of mammals, more than 45% of birds, and 89% of in-shore, temperate-zone fish are endemic. Australia has the greatest number of reptiles of any country, with 755 species. Besides Antarctica, Australia is the only continent that developed without feline species. Feral cats may have been introduced in the 17th century by Dutch shipwrecks, and later in the 18th century by European settlers. They are now considered a major factor in the decline and extinction of many vulnerable and endangered native species. Australian forests are mostly made up of evergreen species, particularly eucalyptus trees in the less arid regions; wattles replace them as the dominant species in drier regions and deserts. Among well-known Australian animals are the monotremes (the platypus and echidna); a host of marsupials, including the kangaroo, koala, and wombat, and birds such as the emu and the kookaburra. Australia is home to many dangerous animals including some of the most venomous snakes in the world. The dingo was introduced by Austronesian people who traded with Indigenous Australians around 3000 BCE. Many animal and plant species became extinct soon after first human settlement, including the Australian megafauna; others have disappeared since European settlement, among them the thylacine. Many of Australia's ecoregions, and the species within those regions, are threatened by human activities and introduced animal, chromistan, fungal and plant species.All these factors have led to Australia's having the highest mammal extinction rate of any country in the world. The federal Environment Protection and Biodiversity Conservation Act 1999 is the legal framework for the protection of threatened species. Numerous protected areas have been created under the National Strategy for the Conservation of Australia's Biological Diversity to protect and preserve unique ecosystems; 65 wetlands are listed under the Ramsar Convention, and 16 natural World Heritage Sites have been established. Australia was ranked 21st out of 178 countries in the world on the 2018 Environmental Performance Index. There are more than 1,800 animals and plants on Australia's threatened species list, including more than 500 animals. 13. Australia boasts a unique biodiversity due to many factors except____.

A、Australia’s long history

B、comfortable habitat

C、highly changeable climate

D、lasting geographic isolation

Find A and B given that the functionis differentiable at.

A、

B、

C、

D、

?A country currently imports automobiles at $8,000 each. Its government believes that, given time, domestic producers could manufacture autos for only $6,000 but that there would be an initial shakedown period during which autos would cost $10,000 to produce domestically. ? a. Suppose that each firm that tries to produce autos must go through the shakedown period of high costs on its own. Under what circumstances would the existence of the initial high costs justify infant industry protection? ? b. Now suppose, on the contrary, that once one firm has borne the costs of learning to produce autos at $6,000 each, other firms can imitate it and do the same. Explain how this can prevent development of a domestic industry and how infant industry protection can help.

Passage 2 On a highway, behind the gate of a vast garden, at the end of which could be discerned the white hues of a pretty manor house bathed in sunlight, was a beautiful, fresh child, clad in those country clothes that are so coquettish. Luxury, freedom from cares, the habitual sight of richest make such children so pretty that one is tempted to consider them molded of a different substance from the children of mediocrity and poverty. Beside him, lying on the grass, was a splendid toy, as fresh as its owner, varnished, gilded, clad in a crimson cloak and covered with plumes and glass beads. But the child was taking no notice of his favorite toy, and this is what he was looking at: On the other side of the gate, out on the roadway, among the nettles and thistles, was another child, dirty, sickly, soiled with soot, one of those pariah-kids in whom an impartial eye would discover beauty, as the eye of a connoisseur can divine an ideal painting underneath a layer of tarnish, if only the repugnant patina of poverty were washed away. -- From “The Poor Child’s Toy” by Charles Baudelaire. The author most likely mentions the physical appearance of the impoverished child in the last paragraph in order to:

A、identify the cause of the child’s poverty.

B、intensify the reader’s sympathetic reaction toward the child.

C、criticize a social upbringing that would allow a child to suffer in such a way.

D、contrast the poverty of the second child with the privilege of the first.

The equation shows that the slope of a plot of chemical potential against pressure is equal to the molar volume of the substance. An increase in pressure raises the chemical potential of any pure substance (because VB > 0). In most cases, VB (l) > VB (s) and the equation predicts that an increase in pressure increases the chemical potential of the liquid more than that of the solid. The effect of pressure in such a case is:

A、To raise the melting temperature slightly.

B、To lower the melting temperature slightly.

C、Negligible. No effect at all.

D、None the above

Everybody loathes it, but everybody does it. A recent poll showed that 40% of Americans hate the practice. It seems so arbitrary, after all. Why does a barman get a tip, but not a doctor who saves lives?

In America alone, tipping is now a ＄16 billion-a-year industry. Consumers acting rationally ought not to pay more than they have to for a given service. Tips should not exist. So why do they? The conventional wisdom is that tips both reward the efforts of good service and reduce uncomfortable feelings of inequality. The better the service, the bigger the tip.

Such explanations no doubt explain the purported origin of tipping—in the 16th century, boxes in English taverns carried the phrase "To Insure Promptitude" (later just "TIP"). But according to new research from Cornell University, tipping no longer serves any useful function.

The paper analyses data from 2,547 groups dining at 20 different restaurants. The correlation between larger tips and better service was very weak: only a tiny part of the variability in the size of the tip had anything to do with the quality of service. Customers who rated a meal as "excellent" still tipped anywhere between 8% and 37% of the meal price.

Tipping is better explained by culture than by economics. In America, the custom has become institutionalized: it is regarded as part of the accepted cost of a service. In a New York restaurant, failing to tip at least 15% could well mean abuse from the waiter. Hairdressers can expect to get 15-20%, the man who delivers your groceries ＄2. In Europe, tipping is less common; in many restaurants, discretionary tipping is being replaced by a standard service charge. In many Asian countries, tipping has never really caught on at all.

How to account for these national differences? Look no further than psychology. According to Michael Lynn, the Cornell paper's co-author, countries in which people are more extrovert, sociable or neurotic tend to tip more. Tipping relieves anxiety about being served by strangers. And, says Mr. Lynn, "In America, where people are outgoing and expressive, tipping is about social approval. If you tip badly, people think less of you. Tipping well is a chance to show off." Icelanders, by contrast, do not usually tip—a measure of their introversion, no doubt.

While such explanations may be crude, the hard truth seems to be that tipping does not work. It does not benefit the customer. Nor, in the case of restaurants, does it actually stimulate the waiter, or help the restaurant manager to monitor and assess his staff. Service people should "just be paid a decent wage" which may actually make economic sense.

Which is tree according to the passage?

A．It is regulated that the customers must pay a tip if they want to get good service.

B．There exists the tipping custom in each country.

C．In some countries, tipping has become an industry.

D．More and more people are in favor of tipping.