please help me all the calculations and explanations

2. Qussnou [ It has been hypothsized that treatments of plastic used in optic lenses will improve wear. Four different treatment. are to be tested. To determine whether any differences in mean wear exist among treatments, 28 castings from a single formulation of the plastic were made and }' castings were randomly assigned to each of the treatments. Wear was determined by measuring the increase in "haze\" after 200 cycles of abrasion {better wear being indicated by smaller increases}. The data collected are reported in the accompanying table. Treatme nt A B 9.15 11.95 13.29 15.15 12.0? 14.?5 11.9? 14.?9 13.31 15.48 12.32 13.4? 11.?8 13.05 21,; 83.90 98.55 8100 25.3? E- 11.935 14.093 12.429 10.910 2.1 Is there evidence at a difference in mean wear among the four treatments? Use at: 0.05. [HINT: Total 35 = 910319 and SST = 363497] 2.2 Estimate the mean difference in \"haze"l increase between treatments B and D, using a 99% condence interval. Interpret your nding