The personnel department of a certain industrial firm used 12 subjects in a study to determine the relationship between job performance rating (y) and scores of four tests. The data are as follows:

Estimate the regression coefficients in the model y = bo + b₁x₁ + b₂x₂ + b₃x₃ + b₄x₄.

71.0 38.5 43.0 11.2 56.5 14.5 59.5 72.5 38.2 44.8 76.0 17.2 69.2 42.5 49.0 17.8 74.5 79.5 43.4 56.3 47.5 19.3 81.2 84.0 60.2 88.0 78.2 24.5 86.2 47.4 62.0 21.2 58.1 80.5 44.5 69.0 48.1 16.9 72.0 41.8 14.8 58.1 68.0 42.1 46.0 60.3 20.0 80.5 85.0 48.1 13.2 58.3 71.0 37.5 47.1 84.0 87.2 65.2 22.5 51.0