Critical Reasoning (CR) | A chemical company claims that, since only one of 520 rats that were

Good question, and here's the thing.

The passage doesn't say that the probability of cancer in rats is 1 in 520 in the sweetener test batch.

Rather, it say that there were 520 rats in the group, and 1 got cancer.

One rat in a group of 520 could get cancer even if, in general, the probability of rats who have been consuming the sweetener getting cancer is actually 1 in 540.

Meanwhile, if only 1 in 520 got cancer, then we can be pretty sure that rats' eating the sweetener doesn't cause the probability to increase to, say, 1 in 100 or 1 in 10.

So, what choice (B) says about the rate of cancer in rats being 1 in 540 indicates that the fact that 1 rat in the group of 520 got cancer indicates that eating the sweetener doesn't cause a significant change in the rate of cancer in rats.

In other
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Statistics : Posted by MartyMurray • on 23 Jan 2008, 22:12 • Replies 20 • Views 27778

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