Split-Plot Design with Factorial Main and Sub-Plots

Split-plot design where the main plots carry A x B and the sub-plots carry C x D. Main-plot sources are tested against Error(a), all other sources against Error(b).

Usage

anova_spd_ab_cd(
  data,
  response,
  main_factor1,
  main_factor2,
  sub_factor1,
  sub_factor2,
  replication,
  verbose = TRUE,
  posthoc = "lsd",
  alpha = 0.05
)

Arguments

data: Data frame containing the experimental data.
response: Name of the response variable.
main_factor1: First main-plot factor (A).
main_factor2: Second main-plot factor (B).
sub_factor1: First sub-plot factor (C).
sub_factor2: Second sub-plot factor (D).
replication: Name of the replication column.
verbose: Logical. If TRUE (default), prints the report.
posthoc: Method for the letters (default "lsd").
alpha: Significance level. Default 0.05.

Value

An object of class aridagri_spd_abcd; see anova_spd_ab_main for the components.

Author

Lalit Kumar Rolaniya, ICAR-IIPR, Bikaner

Examples

data <- expand.grid(rep = 1:3, irrigation = c("I1", "I2"),
                    tillage = c("CT", "ZT"), variety = c("V1", "V2"),
                    nitrogen = c("N1", "N2", "N3"))
set.seed(5)
data$yield <- rnorm(nrow(data), 1200, 80)
res <- anova_spd_ab_cd(data, response = "yield",
                       main_factor1 = "irrigation", main_factor2 = "tillage",
                       sub_factor1 = "variety", sub_factor2 = "nitrogen",
                       replication = "rep", verbose = FALSE)
res$anova_table
#>                                     Df       Sum Sq     Mean Sq     F value
#> rep                                  2  16420.93277  8210.46639 1.105353590
#> irrigation                           1   9360.69652  9360.69652 1.260206061
#> tillage                              1  16439.93329 16439.93329 2.213265171
#> irrigation:tillage                   1     18.10413    18.10413 0.002437311
#> Error(a)                             6  44567.45674  7427.90946          NA
#> variety                              1  37683.26118 37683.26118 8.467106842
#> nitrogen                             2  15213.08351  7606.54176 1.709124946
#> irrigation:variety                   1   3079.15161  3079.15161 0.691859060
#> tillage:variety                      1   6436.68371  6436.68371 1.446267838
#> irrigation:nitrogen                  2   2347.06776  1173.53388 0.263683037
#> tillage:nitrogen                     2  32802.85473 16401.42737 3.685260604
#> variety:nitrogen                     2  19012.37030  9506.18515 2.135958588
#> irrigation:tillage:variety           1   1713.42726  1713.42726 0.384992466
#> irrigation:tillage:nitrogen          2  13070.13055  6535.06527 1.468373335
#> irrigation:variety:nitrogen          2   7678.82966  3839.41483 0.862683710
#> tillage:variety:nitrogen             2  23726.93224 11863.46612 2.665619482
#> irrigation:tillage:variety:nitrogen  2  25790.47466 12895.23733 2.897449659
#> Error(b)                            40 178021.89995  4450.54750          NA
#>                                          Pr(>F)
#> rep                                 0.390222277
#> irrigation                          0.304515100
#> tillage                             0.187392487
#> irrigation:tillage                  0.962227530
#> Error(a)                                     NA
#> variety                             0.005881108
#> nitrogen                            0.193978479
#> irrigation:variety                  0.410471026
#> tillage:variety                     0.236198364
#> irrigation:nitrogen                 0.769541846
#> tillage:nitrogen                    0.033965387
#> variety:nitrogen                    0.131411460
#> irrigation:tillage:variety          0.538462784
#> irrigation:tillage:nitrogen         0.242447177
#> irrigation:variety:nitrogen         0.429730753
#> tillage:variety:nitrogen            0.081893238
#> irrigation:tillage:variety:nitrogen 0.066812490
#> Error(b)                                     NA