agridat (version 1.16)

holtsmark.timothy.uniformity: Uniformity trial of timothy

Description

Uniformity trial of timothy hay circa 1905

Usage

data("holtsmark.timothy.uniformity")

Format

A data frame with 240 observations on the following 3 variables.

row

row

col

column

yield

yield per plot, kg

Details

Field width: 40 plots * 5 m = 200 m.

Field length: 6 plots * 5 m = 30 m

Holtsmark & Larsen used this trial to compare standard deviations of different sized plots (combined from smaller plots).

References

Theodor Roemer (1920). Der Feldversuch.

Examples

# NOT RUN {
data(holtsmark.timothy.uniformity)
dat <- holtsmark.timothy.uniformity

# Define diagonal 'check' plots like Holtsmark does
dat <- transform(dat,
                 check = ifelse(floor((row+col)/3)==(row+col)/3, "C", ""))
                 
if(require(desplot)){
  desplot(yield ~ col*row, data=dat, flip=TRUE, text=check, show.key=FALSE,
          aspect=30/200, # true aspect
          main="holtsmark.timothy.uniformity")
}

sd(dat$yield) # 2.92 matches Holtsmark p. 348

# }