What is the problem of the single case faced by statistical

What is the problem of the single case faced by statistical frequency theory of probability? How is it usually addressed? Is this successful?

Solution

The problem of the single case faces by statistical frequency theory of probability is that it it not effective in providing information at group level.

The single case allows to study longitudinal process of change with better precision than group level design due to higher number of data points.

Yes it is successful as the single case statistical frequency provide highly accurate assessment for individuals rather than groups.