In an article in Public Roads (1983), Bissell, Pilkington, Mason, and Woods study bridge safety y (measured in accident rates per 100 million vehicles) and x, the difference between the width of the bridge and the width of the roadway approach (road plus shoulder). The values of x analyzed by the authors were -6, -4, -2, 0, 2, 4, 6, 8, 10, and 12. The corresponding values of y were 120, 103, 87, 72, 58, 44, 31, 20, 12, and 7. Find and interpret a point estimate of and a 95% confidence interval for the slope, $1, of a simple linear regression model describing these data