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:
H_{0} The fibres are all of equal
strength
H_{1} At least one of the fibres
is of different strength
The analysis is:
Source
of Variation 
Sum
of Squares 
Degrees
of Freedom 
Mean
Square 
F_{0}

pvalue 
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.
