This is an assessment from the Coursera data science course (Developing data products) in week 4. This presentation will introduce you about my Shiny application deployed on Rstudio’s sever.

Here’s the link to the shiny application: https://doublefaces.shinyapps.io/Developing_data_products_week4_Shiny_App/.

This is the link to the Github repository of the ui & sever.R: https://github.com/Doublefacez/Developing-data-products-week-4-Peer-assessment

In this Shiny application, the mtcars data set was used. This application uses different variables to plot against the mpg (Miles per Gallon) variable, also draws a simple regression line of (hp ~ mpg).

head(mtcars)

##                    mpg cyl disp  hp drat    wt  qsec vs am gear carb
## Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
## Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
## Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
## Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
## Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
## Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

library(shiny)

shinyUI(fluidPage(
    titlePanel("Cars Dataset - Miles per Gallon"),
  
  sidebarPanel(selectInput("var", "Variable:", 
                        c("Cylinders" = "cyl", "Transmission type" = "am",
                          "Gears" = "gear")),
            checkboxInput("model", "Show a simple regression model of hp vs mpg", 
                          value = FALSE),
                        submitButton("Sure! It seems cool")
        ),
  mainPanel(
            h3(textOutput("title")),
            plotOutput("plot1"),
            plotOutput("plot2")
  )
))

library(shiny)
library(ggplot2)

data <- mtcars
data$am <- factor(data$am, labels = c("Auto", "Manual"))

shinyServer(function(input, output) {
    fig_title <- reactive({
        paste("mpg vs ", input$var)
    })
    output$title <- renderText({
        fig_title()
    })
    output$plot1 <- renderPlot({
        if(input$var == "cyl"){
            plot(mtcars$cyl, mtcars$mpg, main = "Plot of mpg vs cyl",
                 xlab = "Cylinders", ylab = "Miles Per Gallon (mpg)")
        }
        if(input$var == "am"){
        
            boxplot(mtcars$mpg, mtcars$am, names = c("Auto", "Manual"),
                    main = " Boxplot of mpg of each transmission type ")
        }
        if(input$var == "gear"){
            plot(mtcars$gear, mtcars$mpg,
                    main = " Plot of mpg of each gear", xlim = c(3, 5))
        }

    })
    output$plot2 <- renderPlot({
        if(input$model){
            model1 <- lm(hp~mpg, data = mtcars)
           
                plot(mtcars$mpg, mtcars$hp, xlab = "Miles per Gallon",
                     ylab = "Horsepower", bty = "n", pch = 16,
                     xlim = c(10,35), ylim = c(50, 350))
                abline(model1, col = "red", lwd = 2)
        }
        })
})