Shiny exercises

Sum app

Generate an app template in RStudio (“New file” button)
Modify the template to get an app which asks for two numbers (using numericInput) and returns its sum.
Format the output with the sentence “The sum is” and the result. The number must be in bold (strong).
Alongside with the previous output, show the result with verbatimTextOutput to see the difference.
Add a submitButton and see its effect on the app reactive behaviour.

Download the app “regressio_inicial” from https://github.com/pere-prlpz/classe_shiny
Test it: it’s a very simple app to graphically show to students what is correlation.
Set the default value of sample size to a larger value (anything from 100 to 1000 could be fine).
Modify “r” numericInput to a slideInput to allow correlation from -1 to +1. Choose a suitable step.
Show the regression summary of the depicted scatterplot. Hint: You will need to store the points and the model in a dedicated reactive object since it will be used by two differnt outputs.
The random part of the data distribution changes when any input changes. Make it change only when sample size changes.
Use the “animate” parameter in sliderInput to creat an animation.
Create tabs in the layout. First one will host the current graphic and summary, second one graphics, and third one numerical sumaries. You may want to add a fourth tab for credits.
Show the same scatterplot in first and second tab and the same regression summary in first and third tabs. Hint: Shiny doesn’t like to render twice the same output.
Add graphical summaries (e.g. histogram) of X and y to second tab and numerical summaries (e.g. summary) to third tab.

Create an scoreboard app with buttons for adding local and visitor goals and to reset scoreboard.
Make the app keep a table of goals with team and time.
Add a button to download the table.
Optional: add controls to make corrections on the score.