The answer is: averaged over time, Sheridan attends worship services regularly.
When we use principle of aggregation, we would not rely on single measurement to make a representation of a person's behavior. We rely more on multiple sets of measurements.
From the case above, Sheridan not attending the services for two weeks could be explained by things such as personal issues or physical illness. Since she considers herself as religious who attend regularly, it is very likely that averaged over time, Sheridan attends worship services regularly.