# What does parameter of interest mean in statistics?

Parameters are the unknown numbers that describe the population.

Because we do not know the parameters, we come up with appropriate estimators to carry out significance tests or construct confidence intervals.

An estimator is the function of the random variables $X_1, X_2, \ldots, X_n$. So mathematically, it's expressed like this: $g(X_1, X_2, \ldots, X_n)$ where g is a function. For example, a sample mean, $\frac{\sum_{i=1}^{n} X_i}{n}$ is also an estimator for the population mean $\mu$. The same explanation applies for sample variance and the population variance.

The parameter of interest is the parameter you want to test with an estimator.

What does parameter of interest mean in statistics?