3. In a chemical process development study on yield, four factors are studied, each at two levels, Time (A), concentration (B), pressure (C) and temperature (D), the yield of this process (pounds/minute) are measured, and the following table gives the results: | D Yield -1 -1 -1 -1 | 12 1 -1 -1 -1 18 -1 1 -1 -1 | 13 1 1 -1 -1 16 -1 -1 1 -1 17 1 -1 1 -1 15 -1 1 1 -120 1 1 1 -1 15 -1 -1 - 1 10 1 -1 25 -1 1 -1 1 13 1 -1 1 24 -1 -1 1 1 19 -11 1 21 -1 1 1 17 23 - 1 a) Identify significant factors and interactions that influence the yield b) Plot relevant main effects and interaction charts to illustrate how they affect the yield c) Write down regression model relating yield to the important process variables d) Identify optimal factor levels to maximize the yield