Uniformity trial of tea — eden.tea.uniformity • agridat

Uniformity trial of tea in Ceylon.

data("eden.tea.uniformity")

Format

A data frame with 144 observations on the following 4 variables.

entry

entry number

yield

yield

row

row

col

column

Details

Tea plucking in Ceylon extended from 20 Apr 1928 to 10 Dec 1929. There were 42 pluckings.

The field was divided into 144 plots of 1/72 acre = 605 sq ft. Each plot contained 6 rows of bushes, approximately 42 bushes. (Each row was thus about 7 bushes).

Plots in row 12 were at high on a hillside, plots in row 1 were low on the hill.

Note: We will assume the plots are roughly square: 6 rows of 7 bushes.

Field width: 12 plots * 24.6 feet = 295 feet

Field length: 12 plots * 24.6 feet = 295 feet

Source

T. Eden. (1931). Studies in the yield of tea. 1. The experimental errors of field experiments with tea. Agricultural Science, 21, 547-573. https://doi.org/10.1017/S0021859600088511

References

None

Examples

# \dontrun{

library(agridat)

  data(eden.tea.uniformity)
  dat <- eden.tea.uniformity

  # sum(dat$yield) # 140050.6 matches total yield in appendix A
  # mean(dat$yield) # 972.574 match page 5554

  m1 <- aov(yield ~ factor(entry) + factor(row) + factor(col), data=dat)
  summary(m1)
#>                Df  Sum Sq Mean Sq F value   Pr(>F)    
#> factor(entry)  11  349240   31749   1.365    0.200    
#> factor(row)    11 1293253  117568   5.054 2.38e-06 ***
#> factor(col)    11  335452   30496   1.311    0.228    
#> Residuals     110 2558996   23264                     
#> ---
#> Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

  libs(desplot)
  desplot(dat, yield ~ col*row,
          aspect=1,
          main="eden.tea.uniformity")
  
# }