case1701 {Sleuth2}

Magnetic Force on Printer Rods

Description

Engineers manipulated three factors (with 3, 2, and 4 levels each) in the construction and operation of printer rods, to see if they influenced the magnetic force around the rod.

Usage

case1701

Format

A data frame with 44 observations on the following 14 variables.

Name	Description
L1, L2,..., L11	the magnetic force at each of the equally-spaces positions 1, 2, ..., 11 on the printer rod
Current	electric current passing through the rod, with three levels "0", "250" and "500" (milliamperes)
Configur	a factor identifying the configuration, with two levels "0" and "1"
Material	a factor identifying the type of metal from which the rod was made, with four levels "1", "2", "3" and "4"

Source

Ramsey, F.L. and Schafer, D.W. (2002). The Statistical Sleuth: A Course in Methods of Data Analysis (2nd ed), Duxbury.

Examples

str(case1701)

pca <- princomp(case1701[,1:11])
summary(pca)
# The first 3 principal components account for 99.7% of the variation
screeplot(pca)
# The loadings suggest the following meaningful summaries...
loadings(pca)

overallaverage <- with(case1701, (L1 + L2 + L3 + L4 + L5 + L6 + L7 + L8 + L9 + L10 + L11)/11)
rightleftdiff <- with(case1701, (L9 + L10 + L11)/3 - (L1 + L2 + L3)/3)
middleleftdiff <- with(case1701, L6 - (L1 + L2)/2)

# Note 4 clusters and 1 outlier
pairs(cbind(overallaverage, rightleftdiff, middleleftdiff)) 

fit1 <- lm(overallaverage ~ Current*Configur*Material, case1701)
anova(fit1)