mead.turnip: Density/spacing experiment for turnips in 3 blocks.

Description Usage Format Details Source References Examples

Description

Density/spacing experiment for turnips in 3 blocks.

Usage

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data("mead.turnip")

Format

A data frame with 60 observations on the following 4 variables.

yield

log yield (pounds/plot)

block

block

spacing

row spacing, inches

density

density of seeds, pounds/acre

Details

An experiment with turnips, 3 blocks, 20 treatments in a factorial arrangement of 5 seeding rates (density) and 4 widths (spacing).

Source

Roger Mead. (1988). The Design of Experiments: Statistical Principles for Practical Applications. Example 12.3. Page 323.

References

H. P. Piepho, R. N. Edmondson. (2018). A tutorial on the statistical analysis of factorial experiments with qualitative and quantitative treatment factor levels. Jour Agronomy and Crop Science, 8, 1-27. https://doi.org/10.1111/jac.12267

Examples

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data(mead.turnip)
dat <- mead.turnip

dat$ratef <- factor(dat$density)
dat$widthf <- factor(dat$spacing)

m1 <- aov(yield ~ block + ratef + widthf + ratef:widthf, data=dat)
anova(m1) # table 12.10 in Mead

# Similar to Piepho fig 10
if(require(lattice)) {
  xyplot(yield ~ log(spacing)|ratef, data=dat,
         auto.key=list(columns=5),
         main="mead.turnip - log(yield) for each density",
         group=ratef)
}

Example output

Analysis of Variance Table

Response: yield
             Df  Sum Sq Mean Sq  F value    Pr(>F)    
block         2  3.4168  1.7084  43.6173 1.443e-10 ***
ratef         4 25.6476  6.4119 163.7023 < 2.2e-16 ***
widthf        3  0.9167  0.3056   7.8011  0.000353 ***
ratef:widthf 12  0.9976  0.0831   2.1224  0.038910 *  
Residuals    38  1.4884  0.0392                       
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Loading required package: lattice

agridat documentation built on May 2, 2019, 4:01 p.m.