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I understand that a normal distribution is a continuous distribution, but I came across this question in my test set that baffles me.

Question:
The toy cars produced in a factory have an average weight of 20 lb. The standard deviation of the individual toy cars is 3 lb. We know the weights of each toy car follow a normal distribution. Compute the proportion of 200 toy cars that weigh 14 lb each.

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    $\begingroup$ Is this the exact question? Or was it "at least 14 lb"? or something like that? $\endgroup$ – Peter Flom Oct 2 '13 at 11:26
  • $\begingroup$ This was the exact question. And hence why im confused. I'm thinking i should do a P(13.5<x<14.5) but im not 100% sure $\endgroup$ – james Oct 2 '13 at 11:28
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    $\begingroup$ This is not a very well-worded question, but it is not your fault! The key thing is whether weight is rounded. If it is, then I think your solution is sound. If not, then think about what exactly a "continuous" distribution means. $\endgroup$ – Peter Flom Oct 2 '13 at 11:32
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Taking the question at face value, the answer is zero.

The area under the standard normal density curve at any single point is the area of a line segment, which is always zero.

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