由两个供方提供的同一种产品，其中A供方提供的为20箱共计1000件产品，B供方提供的为40箱共计2000件产品。准备抽检300件产品，①如果把所有的产品编号，按随机数发生器产生的随机数按号码抽取产品，这称为（）法；②把所有产品排序，按一个随机数抽取第一个产品，然后每隔10个号再抽一个，这称为（）法；③随机从A供方的产品中抽取100个，再从B供方的产品中抽取200个产品进行检验，这称为分层抽样法；④从A供方的产品中随机抽取2箱，再从B供方的产品中随机抽取4箱，然后检验抽出的6箱中所有产品，这称为整群抽样法。
参考答案：一般随机抽样；等距抽样
Ali is from a Middle Eastern country. He now stays in the USA. He smokes a lot of cigarettes every day. He has smoked for nine years. Ali says, “I tried to quit smoking in my hometown, but it was impossible. My parents smoke. My brothers smoke. All my friends smoke. At parties and at meetings, almost all the men smoke. Here in the United States, not as many people smoke. 小题1: ” Many smokers are like Ali: they want to stop smoking. 小题2: They know it can cause cancer and heart disease. But it is difficult for them to give up smoking because cigarettes have a drug in them. The drug is nicotine. People who smoke a lot need nicotine. 小题3: The nicotine makes him sick. In a few days, the smoker's body is used to the nicotine, and he feels fine. Later, the smoker needs nicotine to keep feeling fine. Without nicotine, he feels bad. 小题4: Many people who quit will soon smoke again. At a party or at work they will decide to smoke "just one" cigarette. Then they will smoke another cigarette, and another. Soon they become smokers again. 小题5:
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