A study carried out to investigate the relationship between a response variable relating...

A study carried out to investigate the relationship between a response variable relating to pressure drops in a screen-plate bubble column and the predictors x₁ = superficial fluid velocity, x₂ = liquid viscosity, and x₃ = opening mesh size resulted in the accompanying data (“A Correlation of Two- Phase Pressure Drops in Screen-Plate Bubble Column,” Canad. J. of Chem. Engr., 1993: 460–463). The standardized

residuals and h_ii values resulted from the model with just x₁, x₂, and x₃ as predictors. Are there any unusual observations?