This is the 12189th most frequent Spanish word.
investigadas
"Investigadas" means "investigated" (feminine plural).
Here, 'investigadas' is used as a past participle describing how the statistics have been subjected to investigation.
Las estadísticas fueron cuidadosamente investigadas para el reporte.
The statistics were carefully investigated for the report.
In this sentence, 'investigadas' acts as an adjective modifying 'áreas' to indicate the areas that have undergone investigation.
Las áreas investigadas incluyen ciencias sociales y naturales.
The investigated areas include social and natural sciences.
Here, 'investigadas' is a participle within a passive construction describing the action of being investigated that occurred to the subject.