A retrospective observational study which is used in medical and psychological research by checking historic records .
This study looks backwards in history to examine exposures to suspected risk or protection factors in relation to an outcome that is considered at the beginning of the study.
The given statement says that A statistical analyst obtains data about ankle injuries by examining a hospital's records from the past 3 years.
Hence, this is a retrospective observational study.
Well the 384 part is the harder part because it is a more complex number (for humans) so after you find out what 4x384=(1536) then 4x5000 is simple and you just add the two answers together.