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2 -4 -4 -4 -4 -4
S о =1/4∙(6∙10 +7,58∙10 +15,3∙10 +18,9∙10 )=11,945∙10 .
S 2 -2
Root mean square deviation S о= o =3,45∙10 .

Task 4.4
Calculate row variances, if experiment is planning on two
levels through planning matrix. Studied process depends on
two factors. As a result, following values of Y were obtained:
Number of Experimental value of Y
experiment У 1 У 2 У 3 У 4 У aver
1 30 27 18 22
2 20 28 24 23
3 25 22 26 27
4 26 21 29 20

4.4 Evaluation of significance of regression coefficients
On second stage of analysis, examining of significance of
regression coefficients is done. Always one factor is affecting
on change of condition more, while another one is less. To
assess such an impact, importance of each coefficient is
examined in two equivalent ways. In both cases, first, the
variance of regression coefficients is determined by the formula:
S 2
S 2  o . (4. 13)
b i
N (  m  ) 1

In the first method, significance of factors is assessed by
the formula:

b i b i
t   .
ip (4. 14)
S 2
b S
i b
i
t  t (4. 15)
If ip T ,
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