6) to find the average (mean) of something, you add all the numbers together and divide it by the amount of results there are. So:
34.5 + 34.9 + 34.2 + 33.4 +35.9 = 172.9
172.9 / 5 = 34.58
7) percentage change is the difference ÷ original result x 100. So
34.58 - 34.1= 0.48
0.48 ÷ 34.1 X 100 ≈ 1.4%