Hi!

I am trying to understand the Term Vectors API of Elastic Stack but I am not quite sure what the 'Field Statistics' output means.

I tried reading the Elastic document about this but just got confused.

```
Field statisticsedit
Setting field_statistics to false (default is true) will omit :
document count (how many documents contain this field)
sum of document frequencies (the sum of document frequencies for all terms in this field)
sum of total term frequencies (the sum of total term frequencies of each term in this field)
```

this is the part I am referring to and I think I get document count. That is, I think it is the number of terms (field and token pair) in the number of documents.

However, I am not quite sure what the 'sum of document frequencies' and the 'sum of total term frequencies' mean exactly.

Would anyone be able to help me understand these things? ^^

Thank you!