Percentages

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A data set is normally distributed with the *mean* value $\mu = 74.00$ and *standard deviation* $\sigma = 9.00$. What percentage of data values are less than $x = 50.00$

**Answer**

*z-score* of $x=50.00 = z = \frac{x-\mu}{\sigma} = \frac{50.00 - 74.00}{9.00}=-2.67$

The area under the *standard normal distribution curve* to the left of $z=-2.67$ is $0.0038$

The percentage of data values that are less than $x=50.00$ is $0.38$