ST512 Lab 3

# ST512 Lab 3 - ST512 Assignment 3 Due Date September 21...

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Page 1 of 8 ST512 Assignment 3 Due Date: September 21. Assignment Goals: 1. Fit a multiple regression model in R. 2. Gain practice with indicator variables. This lab is based on Ch. 10 of the book StatLabs: Mathematical Statistics Through Applications , by D. Nolan and T. Speed. The data are taken from a larger study, the Child Health and Development Studies (CHDS), which was conducted at the Kaiser Foundation Health Plan in Oakland, CA, from 1960-1967. The data that you will be using in this lab are for all 1174 single male births in a single year of that study where the baby lived at least 28 days. If you are able to access the AFS system, read the data set into R using the command > baby<-read.table("J:/.eos/courses/st/st512/www/lec/001/data/baby.txt",head=T) If you are unable to access the AFS system, this data set (like all data sets used in labs) is stored in a public directory that can be accessed by pointing your web browser to http://courses.ncsu.edu/st512/lec/001/data/ . Copy/paste the data set into a text file on your local computer and change the path in the 'read.table' command above accordingly. The data set “baby” includes the following variables: bwt : The birth weight of the baby, in ounces gestation : The duration of the pregnancy in days, calculated form the first day of the last normal menstrual period. age : The mother’s age at the time of conception, in years height : The mother’s height, in inches weight : The mother’s weight, in pounds smoke : An indicator variable for whether the mother smokes (1) or not (0). Indicator variables: The variable “smoke” is an example of an indicator variable. An indicator variable is a device that is used to incorporate categorical predictors into a regression analysis. Categorical predictors are predictors whose values are categories. Here, the categories for the predictor “smoke” are smokers and non-smokers. These categories are also called the “levels” of the predictor. (All of the other predictors in this data set, as well as the other predictors that we’ve seen in class, are called numeric or quantitative predictors.)

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ST512 Lab 3 - ST512 Assignment 3 Due Date September 21...

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