200 likes | 274 Views
Statistical Analysis. Professor Lynne Stokes Department of Statistical Science Lecture 6QF Multivariate Normal Distribution, Chi-square Distribution of Quadratic Forms, Testing the Significance of Factor Effectrs. Quadratic Forms. Distributional properties of q depend on both
E N D
Statistical Analysis Professor Lynne Stokes Department of Statistical Science Lecture 6QF Multivariate Normal Distribution, Chi-square Distribution of Quadratic Forms, Testing the Significance of Factor Effectrs
Quadratic Forms Distributional properties of q depend on both the properties of the known matrix A and the distribution of the random vector x.
Positive (Semi-) Definite Matrices Properties of the Covariance Matrix • Nonsingular • Symmetric • Positive Definite Similar Definitions: Negative (Semi-) Definite, Indefinite
Trace of a Square Matrix Definition Properties Cyclic Permutations li = eigenvalues of A Symmetric Idempotent Matrix li = 1 or 0
Probability Distribution Sample Variance
Total Sum of Squares Quadratic Form Show Degrees of Freedom n -1 = ar - 1 = rank(AT) = tr(AT)
Main Effect Sum of Squares Quadratic Form Show Degrees of Freedom a -1 = rank(AA) = tr(AA)
Main Effect Sum of Squares Probability Distribution Show
Error Sum of Squares Quadratic Form Degrees of Freedom Show n - a = rank(AE) = tr(AE)
Error Sum of Squares Probability Distribution Show
Independence of the Main Effect and Error Sums of Squares Pairwise Independence of Quadratic forms
Statistical Tests for (Fixed) Main Effects and Interactions :Balanced Complete Factorials Single-Factor Experiment Response Distribution y ~ N(m1 + XAa , s2I)
Statistical Tests for (Fixed) Main Effects and Interactions :Balanced Complete Factorials Distributional Properties SSA & SSE are statistically independent
Statistical Tests for (Fixed) Main Effects and Interactions :Balanced Complete Factorials iff a1 = ... = aa = 0
Testing Factor Effects Single-Factor Model yij = m + ai + eij i = 1, ..., a; j = 1, ..., r Equivalent Simultaneous Test for Main Effects H0: a1 = a2 = ... = aa vs. Ha: aiaj for some (i,j)
Assignment • Verify the ‘Show’ Results