Page 29 - 6686

G  G
Table 4.1. If condition p Т is satisfied, then hypothesis of
homogeneity of variances is accepted.
G
Quantity Т for number of degrees of freedom f 1 = m-1
and f 2 = N and significance level q can be found in table 4.1. For
technical calculations level of significance is 5%: q = 0.05.
G  G
p
If condition Т is not satisfied, then solution is to
increase the number of experiments, conducted parallelly, which
means that matrix of planning must be implemented one or
several time more.
If increase of m (number of experiments, conducted
parallelly) does not give the expected result, accuracy of
method should be increased.
G  G
Under the condition p Т average values of row
variances are:

2 1 N 2
S o    S u 
N u  1
(4.12)
1 N m  2
    y uj  y u
N  m(  1 ) u  1 j  1
,

where N∙(m-1) = f o - number of degrees of freedom.
2
So, it is error experiment S о
S 2
Root mean square deviation or error S о = o

Task 4.3
Calculate row variances (Task 4.1)
Solving:
Table 4.1 - Values of Cochran’s criteria

29