STA302H1 Midterm: UTSG STA 302 t2f05
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Sta 302 / 1001 f - fall 2005. Suppose that x is a 2 1 random vector with e(x) = 1. Y is another random vector with y = ax where a is the constant matrix a = 1 -2. Find the expectation of y and the variance-covariance matrix for y. 2: (14 points) (a) write the simple linear regression model in matrix terms, de ning all terms. (b) explain why cov( ) = 2i follows from the assumptions of simple linear regression. 3 (c) a simple linear regression model is t to data with 18 observations and the following are calculated: Find a 90% con dence interval for the intercept. (d) show b = + r where r = (x x) 1x . Interest is in considering how population can be used to predict the number of breast cancer cases. Questions related to this sas output are on the next 3 pages.
