meterstick: a rule one meter long (usually marked off in centimeters and millimeters)
entity: that which is perceived or known or inferred to have its own distinct existence (living or nonliving)
regression coefficient: when the regression line is linear (y = ax + b) the regression coefficient is the constant (a) that represents the rate of change of one variable (y) as a function of changes in the other (x); it is the slope of the regression line