大数据这两年一直是热词。发展中的大数据确实带来了很多有用信息,但是所谓大数据,并非越大越美,越大越有价值。比如,在美国抽取一个1000人的抽样调查。这个调查若是同样在中国做,要达到同样精度,需要抽取多少人?中国的人口是美国的4倍多一点,每次我在大学讲座问到这个问题,只有10%以下的人说出正确答案——只需抽样1000人,而绝大多数人认为抽 Big data has been a hot word for two years. Big data in development does bring a lot of useful information, but the so-called big data, not the bigger the more the United States, the greater the more valuable. For example, a sample of 1,000 people in the United States is sampled. If this survey was done in China as well, how many people would it be necessary to reach the same precision? China’s population is four times more than that of the United States. Every time I asked this question at a university lecture, only 10% or less of people said the correct answer - Just sample 1000 people, while most people think that smoking