Question 4 (a) A small independent organic food store offers a variety of specialty coffees, To determine whether price has an impact on sales, the manager kept track of how many pounds of each variety of coffee were sold last month. Price per pound Pound sold $3.99 75 $5,99 60 $7.00 65 $12.00 $4.50 $7.50 $15.00 $10,00 35 $12.50 40 58,99 50Simple regression model is fitted to these data, the Microsoft Excel summary output are given as follows. OH 10 ANDYA Aexpoundon Total H.AT JHWrite the regression equation for the data. (2 marks) Does the y-intercept carry any practical interpretation in this problem? Explain your answer. (2 marks) Interpret the slope of the problem in words. (2 marks) (iv) Predict and interpret the sales if the price per pound is $6,00, (2 marks) (v) Interpret the 88% confidence interval estimate of the slope in this problem. (2 marks) (vi) Based on part (v), do the data provide sufficient evidence to conclude that the sales is linearly related to the price? (2 marks) (vii) Interpret the coefficient of determination. " in this problem. (2 marks)(b) A researcher wishes to test the effectiveness of a flu vaccination. Out of a total of 430 people, 150 are vaccinated, 180 are vaccinated with a placcho, and 100 are not vaccinated. The number in each group who later caught the flu was recorded. The results are shown below. Vaccinated Placebo Control Caught the fu 19 21 Did not catch the fu 142 161 79 Use a 5% significance level to test the claim that the proportion of people catching the flu is the same in all three groups. /Nore: the rest statistic nature is 14.965] (6 marks) (c) In the yo test of independence, the test statistic formula used is XSTAT = E all cells Discuss the meaning of f. and f and explain the circumstances under which the Xray values will be smaller or larger. What is the relationship between a significant X-ray and the values of f. and f