# How do I find the Z score for a statistic without standard deviation given Pop mean=.05%, n=100, Sample mean of .11%?

Jun 6, 2015

By definition, Z score is:
$z = \frac{x - \mu}{\sigma}$
where $x$ is your datum, $\mu$ is the mean of your population and $\sigma$ is its standard deviation. Basically, it's a measure of deviation from the mean in units of standard deviation.

Unless I misunderstood your problem, I see no way you can calculate this number without knowing a standard deviation.

Dec 7, 2016