b) A researcher wanted to investigate the effect of chemical grades and brands of drugs on the relief time from headache in (minutes) from patients. A (2x3) two-way ANOVA design was used and the data are as summarized in the following table. Chemical Grades Brand of Drugs B1 B2 B3 Low 15, 17, 21 17, 23, 24 21, 19, 23 High 10, 11, 12 15, 13, 14 17, 18, 21 Analysis of Variance Source Adj SS Adj MS F-Value P-Value Chemical V1 133.39 133.389 F 0.000 Drug V2 92 . 11 G 8. 13 0 . 006 Chemical *Drug V3 E 11. 056 0. 185 Error D 68.00 5. 667 Total 17 315. 61 Assume all the assumptions of ANOVA are met, answer the following questions. i) Find the missing values of D, E, F and G. ii) Test at 5% significance level whether is there a significant interaction effect between chemical grades and brands of drugs on the mean relief time from headaches of the patients? (4 marks) iii) Based on your test in (ii), is it necessary to conduct further test on the effect of chemical grades as well as brands of drugs on the relief time from headache of patients? Explain your answer. (2 marks)