An investigator hypothesizes that head trauma producing unconsciousness during childhood is strongly associated with the development of temporal lobe seizures (TLS) as an adult.

To study this question the investigator performs a case-control study and identifies 100 adults with temporal lobe seizures (cases) and 100 adults from the same community who do not have seizures (controls). The investigator had a history of childhood head trauma producing unconsciousness.

Let us use our flowchart to address our two basic questions in statistical analysis:

1. Estimation: What measurement should be used to summarize the data which has been found in this investigation?

2. Inference: How can we use the study data to investigate whether there is a real association between history of head trauma producing unconsciousness during childhood and temporal lobe seizures as an adult in the population from which the investigator's sample was selected?