Data: {3.9, 2.1, 0.8, 1.5, 4.1}
mean: sum of numbers/total numbers
part A
⇒ mean: (3.9+2.1+0.8+1.5+4.1)/5 = 2.48
part B
If all the data's are increased by 5
{8.9, 7.1, 5.8, 6.5, 9.1}
Then mean ⇒ (8.9+7.1+5.8+6.5+9.1)/5 ⇒ 7.48
part C
If the data is doubled.
{7.8, 4.2, 1.6, 3, 8.2}
Then mean ⇒ (7.8+4.2+1.6+3+8.2)/5 ⇒ 4.96