z-test
The \(z\) test is a statistical test for the mean of a population. It can be used either when \(n\geq30\) or when the population is normally distributed and \(\sigma\) is known.
The formula for the \(z\)-test is:
\[z=\frac{\overline{x}-\mu}{\left(\frac{\sigma}{\sqrt{n}}\right)}\]
The assumptions for confidence intervals when \(\sigma\) is known need to be met to proceed here as well.