并且CDC拥有一个医务人员的网络，这些医务人员常规性的对病人抽样并测试，以检验他们携带哪些可能在社会中流行的致病体。

And the CDC has a network of physicians who routinely sample and test patients to see what bugs they have and might be circulating in the community.

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这是一个简单的帕雷托图表的例子，用抽样资料显示引起网络错误原因的相对频率。

This is a simple example of a Pareto diagram using sample data showing the relative frequency of causes for errors on websites.

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初看上去，人们的社交网络似乎很大，抽样的30万Twitter用户中，平均每人有80个好友（在Facebook里每人有120个好友），个别甚至有上千个好友。

At first glance, the networks seemed enormous—the 300,000 Twitterers sampled had 80 friends each, on average (those on Facebook had 120), but some listed up to 1,000.

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