Zaznacz stronę

Outline 1 Motivation and statistical framework 2 Maths reminder (survival kit) 3 Linear Least Squares (LLS) 4 Non Linear Least Squares (NLLS) 5 Statistical evaluation of solutions 6 Model selection Stéphane Mottelet (UTC) Least squares 2/63 Least Squares Fit (1) The least squares ﬁt is obtained by choosing the α and β so that Xm i=1 r2 i is a minimum. Least Squares Adjustment Using Conditional Equations. Least-squares • least-squares (approximate) solution of overdetermined equations • projection and orthogonality principle • least-squares estimation • BLUE property 5–1. Example from overview lecture u w y H(s) A/D Problems An example of the least squares method is an analyst who wishes to test the relationship between a company’s stock returns, and the returns of the index for which the stock is a component. Learn examples of best-fit problems. Least Squares Fit of Points to a Line or Curve. Summary of computations The least squares estimates can be computed as follows. Including experimenting other more recent methods of adjustment such as: least squares collocation, Kalman filter and total least squares. Figure 2 – Creating the regression line using the covariance matrix. Introduction Vocabulary words: least-squares solution. Hence the term “least squares.” Examples of Least Squares Regression Line FINDING THE LEAST SQUARES APPROXIMATION We solve the least squares approximation problem on only the interval [−1,1]. The least-squares method provides the closest relationship between the dependent and independent variables by minimizing the distance between the residuals, and the line of best fit, i.e., the sum of squares of residuals is minimal under this approach. Section 6.5 The Method of Least Squares ¶ permalink Objectives. A set of large print lecture notes (74 pages) suitable for PowerPoint presentation outlining the least squares principle and its application in the development of combined least squares, indirect least squares (parametric least squares), observations only least squares and Kalman Filtering. In this section, we answer the following important question: Calibration of an EDM Instrument. Least squares method, also called least squares approximation, in statistics, a method for estimating the true value of some quantity based on a consideration of errors in observations or measurements. Learn to turn a best-fit problem into a least-squares problem. The sample covariance matrix for this example is found in the range G6:I8. Picture: geometry of a least-squares solution. the sum of squares (3.6) that makes no use of ﬁrst and second order derivatives is given in Exercise 3.3. Example 11.5 Using Observation Equations. Let ρ = r 2 2 to simplify the notation. The minimum requires ∂ρ ∂α ˛ ˛ ˛ ˛ β=constant =0 and ∂ρ ∂β ˛ ˛ ˛ ˛ α=constant =0 NMM: Least Squares Curve-Fitting page 8 Find α and β by minimizing ρ = ρ(α,β). Least Squares Solution of Nonlinear Systems. A simple numerical example is used to elucidate these basic methods. Least squares estimation Step 1: Choice of variables. Keywords: Least squares, least squares collocation, Kalman filter, total least squares, adjustment computation 1. Approximation problems on other intervals [a,b] can be accomplished using a lin-ear change of variable. The approach is described in Figure 2. Recipe: find a least-squares solution (two ways). 3 The Method of Least Squares 4 1 Description of the Problem Often in the real world one expects to ﬁnd linear relationships between variables. Since we have 3 … To test Example 2: Find the regression line for the data in Example 1 using the covariance matrix. For example, the force of a spring linearly depends on the displacement of the spring: y = kx (here y is the force, x is the displacement of the spring from rest, and k is the spring constant).