Density/spacing experiment for turnips in 3 blocks.

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

# \dontrun{

library(agridat)
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
#> 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

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

# }