raw_vs_resids_shiny_app.R

library("shiny")
library("ggplot2")

n_obs <- 500L

## Define UI for application that draws a histogram
ui <- fluidPage(

  ## Application title
  titlePanel("Visualizing Raw Data vs Residuals"),

  ## Sidebar with a slider input for number of bins
  sidebarLayout(
    sidebarPanel(
      sliderInput("subj_a",
		  "Mean RT for Subject A:",
		  min = 500,
		  max = 900,
		  value = 600),
      sliderInput("subj_b",
		  "Mean RT for Subject B:",
		  min = 500,
		  max = 900,
		  value = 650),      
      sliderInput("subj_c",
		  "Mean RT for Subject C:",
		  min = 500,
		  max = 900,
		  value = 700),      
      sliderInput("subj_d",
		  "Mean RT for Subject D:",
		  min = 500,
		  max = 900,
		  value = 750),      
      sliderInput("subj_e",
		  "Mean RT for Subject E:",
		  min = 500,
		  max = 900,
		  value = 800),
      hr(),
      checkboxInput("reveal", "Reveal subject distributions"),
      actionButton("resample", "New Sample")
    ),

    ## Show a plot of the generated distribution
    mainPanel(
      plotOutput("distPlot"),
      textOutput("sw_raw"),
      hr(),
      plotOutput("residPlot"),
      textOutput("sw_resid")
    )
  )
)

## Define server logic required to draw a histogram
server <- function(input, output) {

  dat <- reactive({
    input$resample
    means <- c(input$subj_a, input$subj_b, input$subj_c,
	       input$subj_d, input$subj_e)
    d1 <- data.frame(subject = rep(LETTERS[1:5], each = n_obs),
	   s_i = rep(means, each = n_obs),
	   e_ij = rnorm(n_obs * 5L, mean = 0, sd = 50))
    d1$y_ij = d1$s_i + d1$e_ij
    d1
  })

  output$distPlot <- renderPlot({
    ## generate bins based on input$bins from ui.R
    if (input$reveal) {
      ggplot(dat(), aes(y_ij, fill = subject)) +
    	geom_histogram(alpha = .2) +
    	ggtitle("Raw Data")
    } else {
      ggplot(dat(), aes(y_ij)) + geom_histogram() +
	ggtitle("Raw Data")
    }
  })

  output$residPlot <- renderPlot({
    ggplot(dat(), aes(e_ij)) + geom_histogram() +
      ggtitle("Residuals")
  })

  output$sw_raw <- renderPrint({
    `(raw data)` <- dat()[["y_ij"]]
    shapiro.test(`(raw data)`)
  })

  output$sw_resid <- renderPrint({
    `(residuals)` <- dat()[["e_ij"]]
    shapiro.test(`(residuals)`)
  })
}

## Run the application
shinyApp(ui = ui, server = server)