You need to first add up the total cost which is 12.45, then find 6% of 12.45 which is .747 or rounded to.75.(tax) then you need to add it to get 13.20. so the tip was 13.20
From the mean of 13, the value of the stated summation will be given by: (5.7-13)+(10.2-13)+(11.9-13)+(13.3-13)+(17.6-13)+(19.3-13) =-7.3+(-2.8)+(-1.1)+0.3+4.6+6.3 =0 Hence the summation indicated also known as mean absolute deviation is 0.
