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Unformatted text preview: Stat 771, Fall 2011: Homework 2 Due Wednesday, February 23 1. The file insulin.dat contains longitudinal data from a study on m = 36 rabbits; 12 rabbits were randomly assigned to each of 3 groups: group 1 rabbits received the standard insulin mixture, group 2 rabbits received a mixture containing 1% less protamine than the standard, and group 3 rabbits received a mixture containing 5% less protamine. Rabbits were injected with the assigned mixture at time 0, and blood sugar measurements taken on each rabbit at the time of injection (time 0) and 0.5, 1.0, 1.5, 2.5, and 3.0 hours post-injection. Each data record in the file insulin.dat represents a single observation; the columns of the data set are (1) rabbit number, (2) hours (time), (3) response (blood sugar level), and (4) insulin group (1, 2, or 3). You may need to transform the data into a form suitable for the various SAS PROCs (or R functions) to accomplish the following. (a) Obtain a profile (spaghetti) plot for each of the three insulin groups with a LOESS smooth superimposed on top. Describe what you see in terms of patterns of blood sugar reduction....
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- Spring '10
- Matrices, Blood sugar, Covariance matrix, Estimation of covariance matrices, Common Covariance Matrix