Artificial example

Description

An artificial data set which causes stepwise regression procedures to select a non-parsimonious model. The true model is a simple linear regression of y against x8.

Usage

1

Format

A data frame with 50 observations on 10 variables.

Details

Inspired by the pathoeg data set in the MPV pacakge.

Examples

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data(artificialeg)
full.mod = lm(y~.,data=artificialeg)
step(full.mod)
## Not run: 
# generating model
n=50
set.seed(8) # a seed of 2 also works
x1 = rnorm(n,0.22,2)
x7 = 0.5*x1 + rnorm(n,0,sd=2)
x6 = -0.75*x1 + rnorm(n,0,3)
x3 = -0.5-0.5*x6 + rnorm(n,0,2)
x9 = rnorm(n,0.6,3.5)
x4 = 0.5*x9 + rnorm(n,0,sd=3)
x2 = -0.5 + 0.5*x9 + rnorm(n,0,sd=2)
x5 = -0.5*x2+0.5*x3+0.5*x6-0.5*x9+rnorm(n,0,1.5)
x8 = x1 + x2 -2*x3 - 0.3*x4 + x5 - 1.6*x6 - 1*x7 + x9 +rnorm(n,0,0.5)
y = 0.6*x8 + rnorm(n,0,2)
artificialeg = round(data.frame(x1,x2,x3,x4,x5,x6,x7,x8,x9,y),1)

## End(Not run)