Step 1: 看到題目，仔細(xì)分析題干，標(biāo)出關(guān)鍵字
　　Step 2: 題目要求選出的是false，然后看各可選內(nèi)容：
　　(i) A simple random sample is a sample selected in such a way that every item in the population has an equal chance of being included.
　　If a sample is selected using random sampling, it will be free from bias (since every item will have an equal chance of being selected). Once the sample has been selected, valid inferences about the population being sampled can be made.
　　所以，符合random sampling， (i) is correct.
　　(ii) A sampling frame is a numbered list of all items in a population. Sampling frame 名單抽樣框：列出所有在總體中的項(xiàng)目名單，并依次編號(hào)。注意Sample（樣本）是在population（總體）中抽出來的，此處概念錯(cuò)誤。
　　所以，(ii) is false.
　　(iii) Cluster sampling 整群抽樣
　　Cluster sampling is a non-random sampling method that involves selecting one definable subsection of the population as the sample, that subsection taken to be representative of the population in question.
　　Cluster sampling是非隨機(jī)抽樣，方法是選定一個(gè)具有代表性的群體作為樣本，來解釋總體。
　　比如，調(diào)查全國(guó)在校小學(xué)生情況，Cluster sampling方法是：選定某所學(xué)校的小學(xué)生進(jìn)行調(diào)查，將該校小學(xué)生的調(diào)查情況（sample）來代表全國(guó)在校小學(xué)生的情況（population）。
　　這種方法的disadvantage是There is potential for considerable bias，而不是選項(xiàng)所述的very little potential for bias。
　　所以，(iii) is false.
　　(iv) In quota sampling, randomness is forfeited in the interests of cheapness and administrative simplicity.
　　Investigators are told to interview all the people they meet up to a certain quota. 這是quota sampling運(yùn)作方式，只要是調(diào)查者遇見的人，即可作為一個(gè)樣本進(jìn)行采訪，直到采訪到指定的樣本量。比較常見的例子是市場(chǎng)調(diào)查，如商業(yè)街上的產(chǎn)品問卷調(diào)查。
　　所以，（iv） is correct.
　　Step 3: 綜合分析，進(jìn)行選擇，注意是選false！