Hat Matrix Pdf
1 0 h ii 1 can you show this.
Hat matrix pdf. The hat matrix H is defined in terms of the data matrix X. The identity matrix is orthogonal. For multiple regression models the formula for calculating the hat matrix diagonal elements h i requires the use of matrix algebra and is.
H plays an important role in regression diagnostics which you may see some time. I The diagonal elements h iiare calledleverages. Just note that yˆ y e I My Hy 31 where H XX0X1X0 32 Greene calls this matrix P but he is alone.
Recall that H h ijn ij1 and h ii X iX T X 1XT i. The hat matrix is a matrix used in regression analysis and analysis of varianceIt is defined as the matrix that converts values from the observed variable into estimations obtained with the least squares method. These estimates will be approximately normal in general.
Myers Montgomery and Vining explain the matrix algebra of OLS with more clarity than any other source Ive found. Leverage is just hii from the hat matrix. Teach with space eet the sense hat 052 3 The Sense HAT is an add-on board for Raspberry Pi that was created for the Astro Pi competition.
The matrix Z0Zis symmetric and so therefore is Z0Z 1. Every diagonal matrix is orthogonal. A projection matrix known as the hat matrix contains this information and together with the Studentized residuals provides a means of identifying exceptional data points.
Hat Matrix Y Xb Y XX0X1X0Y Y HY where H XX0X1X0. Hat Matrix and Leverages Basic idea. Lets look at some of the properties of the hat matrix.