The paper “The Effects of Split Keyboard Geometry on Upper Body Postures” (Ergonomics [2009]:

104–111) describes a study to determine the effects of several keyboard characteristics on typing speed. One of the variables considered was the front-to-back surface angle of the keyboard. Minitab output resulting from fitting the simple linear regression model with x 5 surface angle

(degrees) and y 5 typing speed (words per minute) is given below.

Regression Analysis: Typing Speed versus Surface Angle The regression equation is Typing Speed 5