Assignment 6

The Shiny app has been created using the mtcars data set. The code for the app is given below. The app has been hosted at:

ui<- (fluidPage(
  titlePanel("mtcars dataset"),
  sidebarLayout(
    sidebarPanel(
      sliderInput("bins",
                  "Number of bins:",
                  min = 1,
                  max = 35,
                  value = 12),
      checkboxInput("showmeanstd", 'Show/hide the mean value', value = TRUE),
      sliderInput("sliderMPG",
                  "MPG of a car?",
                  min = 10,
                  max = 35,
                  value = 20),
      checkboxInput("showmodel", 'Show/hide the predicted model', value = TRUE)
    ),
    mainPanel(
      tabsetPanel(
        tabPanel("Plot",
                 fluidRow(
                   column(8, plotOutput("histPlot")),
                   column(8,  h3("Predicted hoursepower from the model:"), textOutput("pred")),
                   column(8, plotOutput("lmplot"))
                 ))
      ))
  )
))

server<- function(input, output) {
  output$histPlot <- renderPlot({
    x    <- mtcars$mpg  
    bins <- seq(min(x), max(x), length.out = input$bins + 1)
    hist(x, breaks = bins, col = 'green', border = 'black', xlab = "MPG")
    if (input$showmeanstd){
      abline(v = mean(x), col = "red", lwd = 2)
      abline(v = c(mean(x) - sd(x), mean(x) + sd(x)), col = "orange", lwd = 3, lty = 2)
    }
  })
  model_lm <- lm(hp~mpg, data = mtcars)
  model_lm_pred <- reactive({
    mpgInput <- input$sliderMPG
    predict(model_lm, newdata = data.frame(mpg = mpgInput))
  })
  output$lmplot <- renderPlot({
    mpgInput <- input$sliderMPG
    plot(mtcars$mpg, mtcars$hp, xlab = "MPG", ylab = "Hoursepower")
    if (input$showmodel){
      abline(model_lm, col = "red", lwd = 2)}
    points(mpgInput, model_lm_pred(), col = "blue", pch = 16, cex = 2)
  })
  output$pred <- renderText({
    model_lm_pred()})
}
shinyServer(function(input, output) {
  output$histPlot <- renderPlot({
    x    <- mtcars$mpg  
    bins <- seq(min(x), max(x), length.out = input$bins + 1)
    hist(x, breaks = bins, col = 'green', border = 'black', xlab = "MPG")
    if (input$showmeanstd){
      abline(v = mean(x), col = "red", lwd = 2)
      abline(v = c(mean(x) - sd(x), mean(x) + sd(x)), col = "orange", lwd = 3, lty = 2)
    }
  })
  model_lm <- lm(hp~mpg, data = mtcars)
  model_lm_pred <- reactive({
    mpgInput <- input$sliderMPG
    predict(model_lm, newdata = data.frame(mpg = mpgInput))
  })
  output$lmplot <- renderPlot({
    mpgInput <- input$sliderMPG
    plot(mtcars$mpg, mtcars$hp, xlab = "MPG", ylab = "Hoursepower")
    if (input$showmodel){
      abline(model_lm, col = "red", lwd = 2)}
    points(mpgInput, model_lm_pred(), col = "blue", pch = 16, cex = 2)
  })
  output$pred <- renderText({
    model_lm_pred()})
})

shinyApp(ui,server)