F₁ + 2F + 3F₃ + mFₘ = 770·9;
whence k = 0·27.
Thus the formula F = 0·27 R is deduced both by the method of least squares, and by the method of graphical construction.
[Table IV].
The formula for this table is to be deduced from the following considerations.
No values exist for x and y, so that the equation
F = x + y R
shall be satisfied for all pairs of values of F and R, but the best values for x and y are those which make
(F₁ - x - y R₁)² + (F₂ - x - y R₂)² + &c. + (Fₘ - x - y Rₘ)²
a minimum.