6. A lecturer gathered data about the amount of time (in hours) students engaged with revision tasks (x), and the percentage scores of those students on the subsequent class test ()). Examination of the raw data suggested that she should use the simple linear regression model to relate these two variables. The values of the revision times ranged from 6.0 to 17.6, and the following summary statistics were found: 1 = 17. Ex = 222.1. Ex = 193.0. 5xx = 155.02, 5vy = 783.88. Sry = 238.11 Page 4 of 10 (a) Calculate a 95% confidence interval for the slope of the least squares model. Pro- vide an interpretation of the interval estimate in the context of the data. Hint: The CI formula for the slope is MSE [6 Marks] (b) Does it appear that there is a statistically significant linear relationship between these two variables? Answer the question by employing the P-value approach. Hint: a test statistic for / = jo is given by MISE [3 Marks]