R/Exam7.2.R

In StroupGLMM: R Codes and Datasets for Generalized Linear Mixed Models: Modern Concepts, Methods and Applications by Walter W. Stroup

#' @title Example 7.2 from Generalized Linear Mixed Models: Modern Concepts, Methods and Applications by Walter W. Stroup (p-219)
#' @name   Exam7.2
#' @description Exam7.2 explains multifactor models with some factors qualitative and some quantitative(Equal slopes ANCOVA)
#' @author \enumerate{
#'          \item  Muhammad Yaseen (\email{myaseen208@@gmail.com})
#'          \item Adeela Munawar (\email{adeela.uaf@@gmail.com})
#'          }
#' @references \enumerate{
#' \item Stroup, W. W. (2012).
#'      \emph{Generalized Linear Mixed Models: Modern Concepts, Methods and Applications}.
#'        CRC Press.
#'  }
#'
#'  @seealso
#'    \code{\link{DataSet7.2}}
#'
#' @import parameters
#' @import emmeans ggplot2
#' @importFrom car Anova
#'
#' @examples
#' library(emmeans)
#' library(car)
#' library(ggplot2)
#'
#' data(DataSet7.2)
#' DataSet7.2$trt <- factor( x = DataSet7.2$trt )
#'
#' ##----ANCOVA(Equal slope Model)
#' Exam7.2fm1 <- aov(formula = y ~ trt*x, data = DataSet7.2)
#' car::Anova(mod = Exam7.2fm1 , type = "III")
#'
#' ##---ANCOVA(without interaction because of non significant slope effect)
#' Exam7.2fm2 <- aov(formula = y ~ trt + x, data    = DataSet7.2)
#' car::Anova(mod = Exam7.2fm2 , type = "III")
#'
#' ##---Ls means for 2nd model
#' emmeans(object  = Exam7.2fm2, specs = ~trt)
#'
#' ##---Anova without covariate
#' Exam7.2fm3 <- aov(formula = y ~ trt, data = DataSet7.2)
#' car::Anova(mod = Exam7.2fm3, type = "III")
#'
#' ##---Ls means for 3rd model
#' emmeans(object = Exam7.2fm3, specs = ~trt)
#'
#' ##---Box Plot of Covariate by treatment
#' Plot <-
#'    ggplot(
#'           data    = DataSet7.2
#'         , mapping = aes(x = factor(trt), y = x)
#'          )                 +
#'    geom_boxplot(width = 0.5) +
#'    coord_flip()            +
#'    geom_point()            +
#'    stat_summary(
#'          fun    = "mean"
#'        , geom     = "point"
#'        , shape    =  23
#'        , size     =  2
#'        , fill     = "red"
#'        )                   +
#'    theme_bw()              +
#'    ggtitle("Covariate by treatment Box Plot") +
#'    xlab("Treatment")
#' print(Plot)
#'
NULL