There is a common belief that the phases of the moon have a powerful influence on behavior. In

fact, the full-moon effect has been studied by a number of researchers. It is believed that the full moon negatively affects psychological functioning. To study this, a researcher analyzes the number of emergency admissions to psychiatric hospitals during nights when the moon is full as opposed to nights when it is not full.

The scores represent the number of admissions to each hospital on a random days throughout the year when the moon was full and a random days throughout the year when the moon was not full.

Is this independent groups t-test or correlated groups t-test and why?