I have a list of documents that belong to a category. Each document has n number of pages. Each page is analyzed with an OCR engine and the time to process each page is saved into a table.
So, I have
CATEGORY | DOC | PAGE | TIME
1 1 1 2
1 1 2 3
1 2 1 3
1 3 3 4
1 3 2 4
2 5 1 5
...
Now, I am grouping these documents to calculate the average time to process their pages. For instance,
CATEGORY | DOC | AVG TIME
1 1 2.5
1 2 3
...
Now, I'd like to know the actual average to process a page per category. But adding these averages and dividing by the number of docs within that category does not make any sense to me.
What can I do to do this? Can I calculate a weighted average in this case? How?
Thanks