Q. 12) A local transit authority for a metropolitan city wants to determine whether there is any relationship between the age of a bus and the daily maintenance cost. Data on a random sample of 12 buses resulted in the following. 10 11 18 20 22 26 30 38 42 46 50 55 Age of Bus (X) (in months) Daily Maintenance Cost (in Rs) (Y) 50 40 60 50 70 60 80 70 80 90 80 100 { x= 368 : Ly = 830 ; x2 = 13,854; _y2 = 60,900: _ xy = 28,180 Fit the linear regression model y = a + Bx + ii) Carryout a test for Ho B = 1 against H:B1 at 5% level of significance. iii) Calculate the proportion of variability explained by this model and comment on the result. iv) Calculate a 95% confidence interval for the daily maintenance cost for an individual bus aged 34 months