a) State the linear regression equation. b} Can you interpret the meaning of the y-intercept in the context of this study? Explain. c) Interpret the slope of the regression equation in the context of these variables. d} Perform the hypothesis test for the slope, and give your conclusion in words, in the context of the variables. [2+2+2+2 = 8 marks] 1.8 Two laboratory procedures for determining the amylase level in human body fluids were compared. The new method is less expensive than the existing method, but may give different results. To compare, both methods were used on each of 10 subjects, with the following results (amylase level in units per millilitre}: Subject Existing method New method 1 38 36 2 48 51 3 58 61 4 53 48 5 79 75 6 68 67 7 73 68 8 57 59 9 83 79 10 72 74 a) Explain why the results should be analysed as paired data. b} Do the methods differ significantly for the level of amylase determined? Carry out a hypothesis test (including all the steps) and write your conclusion in plain English. Use a significance level of 10%. c) Calculate a 90% confidence interval for the difference in amylase level for the two methods, and interpret your interval. d} Based on your hypothesis test result, did you expect to find 0 in the interval? Explain. [1+5+3+1 = 10 marks]