Tip Calculator

Alper Gondiken

2014-07-27

Executive Summary

Scenario: You go to a restaurant and don't know how much you should tip

This application helps you to calculate the tip you could leave, based on:

Your bill
Size of your group (# of people)
Your thoughts about the restaurant

Access to application

How it works

You input your bill amount on the slider in the sidebar

You input number of people dining on the second slider in the sidebar

Then you input your thoughts about the place by checking out the boxes in the sidebar

Was the waitress a smiling person?
Did the food arrive on time?
Was the overall service high quality?
Was the food delicious?

bill

size

feedback

Example

You and your three friends had dinner and your bill is £72

Your feedbacks are “Waitress was a smiling person” and “Service quality was high”

bill <- 72
size <- 4
feedback <- c("Smiling","High-quality")

allpage

Model in the background

Each positive feedback results in additional 5% tip on top of the min 5% (social norm)

Each additional person in the dining group will decrease the tip by 1%*

As the bill increases, tips tend to decrease percentage-wise*

*: Information comes from the research

tipModel <- function(bill,feedback,size){
  #Every positive feedback counts for 5% tip on top of 5% minimum
  feedback.reward <- length(feedback)*0.05 + 0.05
  #Every incremental person in the group reduces the bill by 1%
  size.penalty <- (1 - size*0.01)
  #People tend to pay percentage-wise less tips when the bill is higher
  bill.penalty <- (1 - bill*0.001)
  tip <- round(bill*feedback.reward*size.penalty*bill.penalty,1)
  tip
}

In the example from previous page, calculate the tip amount and total payment amount:

tipModel(bill,feedback,size) #Tip amount

[1] 9.6

bill + tipModel(bill,feedback,size) #Total payment

[1] 81.6