Confidence interval of a standard deviation and a mean

When we consider a few values in a sample, the parameters calculated are merely estimators of the parameters we're looking for. The empirical mean is an estimate of the mathematical expectation of the parent population. The experimental standard deviation is also only an estimate. In order to describe reality more accurately, it is possible to evaluate estimates by confidence intervals, to take account of the sampling effect and thus give a more accurate idea of the possible values of the parameters of the parent law.