In: Statistics and Probability
It has been hypothesized that treatment after casting, of a plastic used in optic lenses will improve wear. Four treatments (A – D) 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 seven 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 indicated by smaller increases). The results are given in the table.
A |
B |
C |
D |
9.16 |
11.95 |
11.47 |
11.35 |
13.29 |
15.15 |
9.54 |
8.73 |
12.07 |
14.75 |
11.26 |
10.00 |
11.97 |
14.79 |
13.66 |
9.75 |
13.31 |
15.48 |
11.18 |
11.71 |
12.32 |
13.47 |
15.03 |
12.45 |
11.78 |
13.06 |
14.86 |
12.38 |