| One Way ANOVA
is used to determine whether varying the
levels or values of a single factor affect
a process. The following data show the strength
of a fibre with varying percentages of a
synthetic material:
| |
1 |
2 |
3 |
4 |
5 |
|
15% |
8 .7 |
9.8 |
12.2 |
12.9 |
9.5 |
|
20% |
14.5 |
17.3 |
14.9 |
15.5 |
12.7 |
|
25% |
16.0 |
13.8 |
18.3 |
17.2 |
18.0 |
|
30% |
23.8 |
21.5 |
18.3 |
24.3 |
22.9 |
|
35% |
9.0 |
14.3 |
10.0 |
14.3 |
7.1 |
An ANOVA analysis tests the hypothesis:
H0 The fibres are all of equal
strength
H1 At least one of the fibres
is of different strength
The analysis is:
| Source
of Variation |
Sum
of Squares |
Degrees
of Freedom |
Mean
Square |
F0
|
p-value |
|
Factor |
448.32 |
4 |
112.08 |
21.78 |
0 |
|
Error |
102.91 |
20 |
5.15 |
|
|
|
Total |
551.23 |
24 |
|
|
|
The alternative hypothesis is accepted,
at least one of the fibres has a different
mean strength.
|
