The manager of a soft drink company collects monthly data on advertising expenditure (X) and sales (Y) in thousands of pounds over a 48 month period. She finds that X has a sample mean of 35.67 and sample variance of 127.47; whilst Y has a sample mean of 42.17 and a sample variance of 280.57. additionally, the sample covariance between X and Y is 133.56 and the sample correlation coefficient is 0.85. she asks you to estimate the following linear regression: