Now the intervention studies are stronger methods than the epidemiology studies but they're also more difficult studies to do.

相比传染病学研究,干预性研究更有效,但也更难执行

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

So now, in this case, this code is going to, when we get here, check, and if you haven't seen that strange thing there, that exclamation point in bang computer-ese called a bang, it says x if ANS star ANS is not equal to x, all right?

那么现在，在这个例子中，当我们执行到这里，代码会去检查,如果你没有看到过这个奇怪的东西,这个感叹号在计算机学中被叫做,代码的意思是如果ANS的平方不等于？

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