Given enrolment of a school during six consecutive years as follows
1555, 1670, 1750, 2019, 2540, 2820
The mean enrolment = Sum of the enrolments in each year/ Total number of years
The mean enrolment = (1555 + 1670 + 1750 + 2019 + 2540 + 2820) ÷ 6
= 12354 ÷ 6
= 2059.
Thus, the mean enrolment of the school for the given period is 2059.