Data from an Oats Field Trial

Description

The yield of oats from a split-plot field trial using three varieties and four levels of manurial treatment. The experiment was laid out in 6 blocks of 3 main plots, each split into 4 sub-plots. The varieties were applied to the main plots and the manurial treatments to the sub-plots.

Usage

oats

Format

This data frame contains the following columns:

B

Blocks, levels I, II, III, IV, V and VI.

V

Varieties, 3 levels.

N

Nitrogen (manurial) treatment, levels 0.0cwt, 0.2cwt, 0.4cwt and 0.6cwt, showing the application in cwt/acre.

Y

Yields in 1/4lbs per sub-plot, each of area 1/80 acre.

Source

Yates, F. (1935) Complex experiments, Journal of the Royal Statistical Society Suppl. 2, 181–247.

Also given in Yates, F. (1970) Experimental design: Selected papers of Frank Yates, C.B.E, F.R.S. London: Griffin.

References

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.

Examples

oats$Nf <- ordered(oats$N, levels = sort(levels(oats$N)))
oats.aov <- aov(Y ~ Nf*V + Error(B/V), data = oats, qr = TRUE)
summary(oats.aov)
summary(oats.aov, split = list(Nf=list(L=1, Dev=2:3)))
par(mfrow = c(1,2), pty = "s")
plot(fitted(oats.aov[[4]]), studres(oats.aov[[4]]))
abline(h = 0, lty = 2)
oats.pr <- proj(oats.aov)
qqnorm(oats.pr[[4]][,"Residuals"], ylab = "Stratum 4 residuals")
qqline(oats.pr[[4]][,"Residuals"])

par(mfrow = c(1,1), pty = "m")
oats.aov2 <- aov(Y ~ N + V + Error(B/V), data = oats, qr = TRUE)
model.tables(oats.aov2, type = "means", se = TRUE)

Results

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> library(MASS)
> png(filename="/home/ddbj/snapshot/RGM3/R_CC/result/MASS/oats.Rd_%03d_medium.png", width=480, height=480)
> ### Name: oats
> ### Title: Data from an Oats Field Trial
> ### Aliases: oats
> ### Keywords: datasets
> 
> ### ** Examples
> 
> oats$Nf <- ordered(oats$N, levels = sort(levels(oats$N)))
> oats.aov <- aov(Y ~ Nf*V + Error(B/V), data = oats, qr = TRUE)
> summary(oats.aov)

Error: B
          Df Sum Sq Mean Sq F value Pr(>F)
Residuals  5  15875    3175               

Error: B:V
          Df Sum Sq Mean Sq F value Pr(>F)
V          2   1786   893.2   1.485  0.272
Residuals 10   6013   601.3               

Error: Within
          Df Sum Sq Mean Sq F value   Pr(>F)    
Nf         3  20020    6673  37.686 2.46e-12 ***
Nf:V       6    322      54   0.303    0.932    
Residuals 45   7969     177                     
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
> summary(oats.aov, split = list(Nf=list(L=1, Dev=2:3)))

Error: B
          Df Sum Sq Mean Sq F value Pr(>F)
Residuals  5  15875    3175               

Error: B:V
          Df Sum Sq Mean Sq F value Pr(>F)
V          2   1786   893.2   1.485  0.272
Residuals 10   6013   601.3               

Error: Within
            Df Sum Sq Mean Sq F value   Pr(>F)    
Nf           3  20020    6673  37.686 2.46e-12 ***
  Nf: L      1  19536   19536 110.323 1.09e-13 ***
  Nf: Dev    2    484     242   1.367    0.265    
Nf:V         6    322      54   0.303    0.932    
  Nf:V: L    2    168      84   0.475    0.625    
  Nf:V: Dev  4    153      38   0.217    0.928    
Residuals   45   7969     177                     
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
> par(mfrow = c(1,2), pty = "s")
> plot(fitted(oats.aov[[4]]), studres(oats.aov[[4]]))
> abline(h = 0, lty = 2)
> oats.pr <- proj(oats.aov)
> qqnorm(oats.pr[[4]][,"Residuals"], ylab = "Stratum 4 residuals")
> qqline(oats.pr[[4]][,"Residuals"])
> 
> par(mfrow = c(1,1), pty = "m")
> oats.aov2 <- aov(Y ~ N + V + Error(B/V), data = oats, qr = TRUE)
> model.tables(oats.aov2, type = "means", se = TRUE)
Tables of means
Grand mean
         
103.9722 

 N 
N
0.0cwt 0.2cwt 0.4cwt 0.6cwt 
 79.39  98.89 114.22 123.39 

 V 
V
Golden.rain  Marvellous     Victory 
     104.50      109.79       97.63 
Warning message:
In model.tables.aovlist(oats.aov2, type = "means", se = TRUE) :
  SEs for type 'means' are not yet implemented
> 
> 
> 
> 
> 
> dev.off()
null device 
          1 
>