For each summarized field there are five available calculations:
Calculation  | 
Results  | 
Sum  | 
Total of all values which are processed. (Numeric fields only)  | 
Minimum  | 
Lowest value.  | 
Maximum  | 
Highest value  | 
Average  | 
Average value (sum divided by count). (Numeric fields only)  | 
Count  | 
Number of values which are processed. Counting, for example, a person's code, if a single person has three records, he counts three times.  | 
Unique count  | 
Number of unique values which are processed. In the example above, that person would count only once.  |