Civil engineers often use the straight line equation, y hat…
Civil engineers often use the straight line equation, y hat = ax + b, to model the relationship between the mean shear strength of masonry joints and precompression stress, x. To test this theory, a series of stress tests were performed on solid bricks arranged in triplets and joined with mortar. The precompression stress was varied for each triplet and the ultimate shear load just before failure (called shear strength) was recorded. The stress results for n=7 triplet tests is shown in the accompanying table. Give a practical interpretation of the estimate of the y-intercept of the least squares line, y hat = .987x + 1.19.