The way I would do it would be to add a hidden field in the repeating table called number with rules on the checkbox to make the number 1 if checkbox is checked and 0 if it gets unchecked.
Then I would have 2 more hidden fields outside the repeating table one called count and one called total with the default values of each count([checkbox field name here]) and sum([number field name here])
Then I would put some rules on the submit button where the conditions would be if count = 0 then set status to Pending,
if count is greater than 0 and count is less than total then set status to Partial Approved,
if count is equal to total then set status to Approved
There may be an easier way but this is what I could come up with.
Hope this helps,