Studies show that 9 out of 10 bicycle riders wear helmets. If 400 bicycle riders are randomly observed, you should expect that there would be an 80% chance that at least how many would be wearing helmets?
Added by Michele J.
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This is equivalent to 90% of bicycle riders. If we observe 400 bicycle riders, we would expect that 90% of them, or 360, would be wearing helmets. However, the question asks for an 80% chance. This means we need to find a number of helmet-wearing riders such Show more…
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