lsmeans (version 1.10-3)

fiber: Fiber data

Description

Fiber data from Montgomery Design (8th ed.), p.656 (Table 15.10). Useful as a simple analysis-of-covariance example.

Usage

fiber

source

Montgomery, D. C. (2013) Design and Analysis of Experiments (8th ed.). John Wiley and Sons, ISBN 978-1-118-14692-7.

Details

The goal of the experiment is to compare the mean breaking strength of fibers produced by the three machines. When testing this, the technician also measured the diameter of each fiber, and this measurement may be used as a concomitant variable to improve precision of the estimates.

Examples

require(lsmeans)
fiber.lm <- lm(strength ~ diameter + machine, data=fiber)
lsmeans(fiber.lm, pairwise ~ machine)