d) Milka Chocolate Bhd. is interested in evaluating the relationship between the number of chocolate bars produced, with the production line speed and Types of Machine (1, 2 and 3) used. Initially, the company fit a multiple linear regression model and obtained fitted function as follows: Y =1.67 + 2.56X; +1.567X2 + 2.301X3 Note: *is significant parameter at 5 % significance level where Y = Number of chocolates bars (in thousand units) X, =Line speed (in seconds) X2- 1 if using Machine 1 0 otherwise if using Machine 2 otherwise i) Variables X, and Xs are found to be significant but X2 is not significant at a=0.05. Explain the meaning of these findings in the context of the problem. (3 marks) ii) The 99% confidence interval for the mean response when X, = 150 and X, =1 is ranging from 11.45 to 16.49. Explain the meaning of this interval. (2 marks)