In the formula for Z-test statistic $Z=\frac{\overline{x}-\mu_0}{\frac{σ}{\sqrt{n}}}$, mark the incorrect statement.
Answer & explanation
Correct answer: option 4
Given Z-test statistic
$Z=\frac{\bar{x}-\mu_0}{\frac{\sigma}{\sqrt{n}}}$
Where
$\bar{x}$ = sample mean
$\mu_0$ = population mean
$n$ = sample size
$\sigma$ = population standard deviation
Thus the statement saying $\sigma$ is population variance is incorrect.
The incorrect statement is: $\sigma$ is variance of the population.