getPoolsComparisionTable: Get Pools Frequency Table
Description
`getPoolsComparisionTable()` produces a frequency table for positive, negative, and pending pools counts by year and
species. The more years present in the data, the larger the table.
Calculation interval for comparison table, accepts “collection_date”,“Biweek”,“Week”, and “Month
target_disease
The disease to calculate infection rate for–i.e. “WNV”.
Disease acronyms are the accepted input. To see a list of disease acronyms, run `unique(pools$target_acronym)`
separate_by
Separate/group the calculation by 'trap','species' or 'agency'. Default NULL does not separate.