Dr. Undómiel has decided to focus on the change in size of a few target rodent species over the course of the experiment(1977-2002). She has chosen , Dipodymys spectabilis, Onychomys torridus, Perymiscus erimicus, Chaetodipus penicillatus.
Write a script that uses R and SQL to:
portal_mammals.sqlite.year, species_id, and the average weight per 
year (avg_weight) for each target species.dbWriteTable() to include your new data frame in the 
portal_mammals.sqlite. Call it something informative so that Dr. Undómiel can 
find it easily.