# What is the z-score of sample X, if n = 49, mu= 75, SD =42, and E[X] =88?

Nov 12, 2016

The z-score $= \frac{13}{6}$

#### Explanation:

The z-score for a sample mean is $\frac{\overline{x} - \mu}{\frac{\sigma}{\sqrt{n}}}$

$\overline{x} = 88$
$\mu = 75$
$\sigma = 42$
$n = 49$

$\therefore$ z-score $= \frac{88 - 75}{\frac{42}{\sqrt{49}}} = \frac{13}{\frac{42}{7}} = \frac{13}{6}$
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