Sugar beets data — data-beets • pbkrtest

Yield and sugar percentage in sugar beets from a split plot experiment. The experimental layout was as follows: There were three blocks. In each block, the harvest time defines the "whole plot" and the sowing time defines the "split plot". Each plot was \(25 m^2\) and the yield is recorded in kg. See 'details' for the experimental layout. The data originates from a study carried out at The Danish Institute for Agricultural Sciences (the institute does not exist any longer; it became integrated in a Danish university).

beets

Format

A dataframe with 5 columns and 30 rows.

Details

  
Experimental plan
Sowing times            1        4. april
                        2       12. april
                        3       21. april
                        4       29. april
                        5       18. may
Harvest times           1        2. october
                        2       21. october
Plot allocation:
               Block 1     Block 2     Block 3
            +-----------|-----------|-----------+
      Plot  | 1 1 1 1 1 | 2 2 2 2 2 | 1 1 1 1 1 | Harvest time
       1-15 | 3 4 5 2 1 | 3 2 4 5 1 | 5 2 3 4 1 | Sowing time
            |-----------|-----------|-----------|
      Plot  | 2 2 2 2 2 | 1 1 1 1 1 | 2 2 2 2 2 | Harvest time
      16-30 | 2 1 5 4 3 | 4 1 3 2 5 | 1 4 3 2 5 | Sowing time
            +-----------|-----------|-----------+

References

Ulrich Halekoh, Søren Højsgaard (2014)., A Kenward-Roger Approximation and Parametric Bootstrap Methods for Tests in Linear Mixed Models - The R Package pbkrtest., Journal of Statistical Software, 58(10), 1-30., https://www.jstatsoft.org/v59/i09/

Examples

data(beets)

beets$bh <- with(beets, interaction(block, harvest))
summary(aov(yield ~ block + sow + harvest + Error(bh), beets))
#> 
#> Error: bh
#>           Df Sum Sq Mean Sq  F value   Pr(>F)    
#> block      2   11.3     5.7    4.018 0.199292    
#> harvest    1 1725.2  1725.2 1225.000 0.000815 ***
#> Residuals  2    2.8     1.4                      
#> ---
#> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
#> 
#> Error: Within
#>           Df Sum Sq Mean Sq F value   Pr(>F)    
#> sow        4   8369  2092.3   119.7 1.13e-13 ***
#> Residuals 20    349    17.5                     
#> ---
#> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
summary(aov(sugpct ~ block + sow + harvest + Error(bh), beets))
#> 
#> Error: bh
#>           Df  Sum Sq Mean Sq F value Pr(>F)  
#> block      2 0.03267 0.01633   2.579 0.2794  
#> harvest    1 0.09633 0.09633  15.211 0.0599 .
#> Residuals  2 0.01267 0.00633                 
#> ---
#> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
#> 
#> Error: Within
#>           Df Sum Sq Mean Sq F value   Pr(>F)    
#> sow        4   1.01  0.2525     101 5.74e-13 ***
#> Residuals 20   0.05  0.0025                     
#> ---
#> Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1