Why is it mathematically impossible to construct a confidence interval that guarantees 100% coverage of the true population parameter?

Answer

The margin of error would have to extend infinitely in both directions, making the estimate useless.

To guarantee 100% coverage, the margin of error must be infinite, resulting in an interval spanning all possible values, which provides no useful information about the parameter.

Why is it mathematically impossible to construct a confidence interval that guarantees 100% coverage of the true population parameter?
estimatestatisticinferenceprecisionconfidence interval