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#  20110208-wheat3.R
#
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# This file shows you how I created the wheat3 dataset using R. 
#


# Set the random number seed so I can replicate my results
set.seed(7) 

ppp <- 5

# Define the variable road as the position of the plot of land with respect to the road.
road <- c( rep("A",3*ppp),rep("B",3*ppp),rep("C",3*ppp) )

# Define the variable fertilizer to specify which type of fertilizer we used on each plot
fertilizer <- rep( c("N18P51K20","N13P00K44","N18P18K18"),3*ppp )

# Create a dependence between the expected wheat height and the plot position and the fertilizer used
m <- 100 + (fertilizer=="N18P51K20")*10 - (fertilizer=="N18P18K18")*10 - (road=="A")*25 - (road=="B")*10

# Create a constant standard deviation
s <- 3

# Create the height variable
height <- floor( rnorm(length(m), m, s) )

# Put the four variables together into one dataframe
wheat3 <- data.frame(species="Triticum polonicum", fertilizer=fertilizer, strip=road, height=height)

# Write this data to a csv file
write.csv(wheat3, "wheat3.csv", row.names=FALSE)