One component of college expenses is your book costs. A sample of students indicates that the average book cost for a semester is 260 dollars and the standard deviation is 50 dollars. If nothing is known about the shape of the book cost distribution, what percentage of the students would have book costs that exceeded 460 dollars?

Answer :

Given inf :

The population mean $(μ) = 260$

The population standard deviation $(σ) = 50$

Solution :

The percentage of the students would have book costs that exceeded 460 dollars :

$∴ P (x > 460) = P (\frac{x - μ}{σ} > \frac{460 - 260}{50})$ $= P (z > 4)$ $\approx 0.003 %$

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