Mean or average is the sum of the numbers divided by the number of pieces of data.
For example, the average of 2,4,6 is (2+4+6 )/3=4.
Similarly, the total number of hours worked over 3 days is (6+5+4)=15 hours over three days. So the average, or
mean = (6+5+4)/3 = 15/3=5 hours.
