Using the model equation in coded units and levels of factor

Using the model equation in coded units and levels of factors A, B and C in the table below (actual levels), estimate the response Y at the midpoint of the factor levels. The runs in the table are listed in standard order Y = 77.88 +84.25A - 24.75B - 10.25C - 11.25AB

Solution

The mid point of the factor level A is 103.25

Level B is 4 and level C is 3.5

Hence the estimated response at the mid point of the levels A B and C is

Y = 3995.5675