agridat (version 1.23)

stirret.borers: Corn borer control by application of fungal spores.

Description

Corn borer control by application of fungal spores.

Format

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

block

block, 15 levels

trt

treatment, 4 levels

count1

count of borers on August 18

count2

count of borers on October 19

Details

Experiment conducted in 1935, Ottawa. European corn borer infestation was established by application of egg masses to plants. Treatments were applied on July 8 and July 19 at two levels, 0 and 40 grams per acre. The number of borers per plot were counted on Aug 18 and Oct 19.

Examples

if (FALSE) {
  
  library(agridat)
  data(stirret.borers)
  dat <- stirret.borers

  libs(lattice)
  xyplot(count2~count1|trt,dat,
         main="stirret.borers - by treatment",
         xlab="Early count of borers", ylab="Late count")
  
  # Even though the data are counts, Normal distribution seems okay
  # qqmath(~count1|trt, dat, main="stirret.borers")
  
  m1 <- lm(count1 ~ -1 + trt + block, dat)
  anova(m1)
  # predicted means = main effect + average of 15 block effects
  # note block 1 effect is 0
  # coef(m1)[1:4] + sum(coef(m1)[-c(1:4)])/15
  ##  trtBoth trtEarly  trtLate  trtNone 
  ## 47.86667 62.93333 40.93333 61.13333 
  
}