Half-fractional factorial design

Halcon Process, t-butyl hydroperoxide, 428 Half-fractional factorial design, analytical methods, 624... 

Let us first consider a half-fraction factorial design. Only half of the number of experiments needed for a full factorial are performed. For... 

SELECTION OF A HALF-FRACTION FACTORIAL DESIGN FROM A FULL FACTORIAL DESIGN FOR 4 FACTORS... 

In terms of absolute size, main effects tend to be larger than two-factor interactions, which in turn tend to be larger than three-factor interactions, and so on. In the half-fraction factorial design of Table 3.9 the main effects are expected to be significantly larger than the three-factor interactions with which they are confounded. As a consequence it is supposed that the estimate for the main effect and the interaction together is an estimate for the main effect alone. 

THE COLUMNS OF CONTRAST COEFFICIENTS FOR THE THREE-FACTOR INTERACTIONS OF THE HALF-FRACTION FACTORIAL DESIGN FOR FOUR FACTORS SELECTED FROM TABLE 3.8... 

Let us now consider how one selects the experiments from the full factorial to obtain a proper half-fraction factorial design. In practice, to construct a... 

A reflected half-fraction factorial design for three factors (2 ) was performed. The influence of the factors on the responses recovery (%), resolution between peaks R) and Ry-value was calculated. Approximate critical values were obtained using the method given by Youden and Steiner (Ecritical MSE)e)- The standard error was estimated from... 

If it is suspected that the probability of significant three- and higher-order interactions is negligible, it will suffice to make 16 (those marked with an asterisk) instead of 32 experiments which is a considerable gain in resources and time. This experimental design is called a half-fractional factorial design [29],... 

Exercise 4.9. In a half-fractional factorial design of resolution VI, the main effects... 

The star-labeled experiments represent the half-fraction factorial design ... 

A fractional factorial and central composite design was used to optimise the measurement of Te by ETAAS. Half fractional factorial designs, central composite designs and response surfaces were applied to find the optimum levels of significant variables. 

To develop a dispersive liquid-liquid microextraction method for Te determination several variables were optimised. A half fractional factorial design (32 experiments) was used to estimate the most effective parameters on the enrichment factor. Then, a half fractional central composite face centred design for five factors was performed to optimise the parameters. 

Table 2 is a half-fraction of a full 2 design. Looking carefully at these experiments one can see that the combination of each set of three variables, for example B, C, and D. constitutes a full 2 design. One says then that the full factorial for By C, and D is embedded in the half-fraction factorial design. This also means that, if D is found to be unimportant, one can interpret the experiment as a full factorial design for factors A, B, and C without any confounding between interactions of the remaining factors. 

Table 1. Half fractional factorial design to produce injection molded plaques with CBA masterbatch... 

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