Impact of having a Waiter Service on the number of Yelp tips per business






Franci Jerič

Primary Question

  • Do the businesses with Waiter Service have a greater number of Yelp tips per business, than businesses without Waiter Service?
  • Our hypothesis is that businesses with Waiter Service tends to have larger number of Yelp tips per business than the businesses without Waiter service
  • Quantifying the difference in number of Yelp tips is of interest to business owners.



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Methods

  • Shapiro-Wilks normality test

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  • Wilcoxon–Mann–Whitney test
    • Null hypothes: Data from both groups (with or without Waiter Service) are coming from the same population
    • Alternative hypothesis: Group with Waiter Service tends to have larger number of Yelp tips than the group without Waiter service
  • Cliff's delta for calculating effect size

Results

  • With p-value is less than \( \alpha=0.01 \) we reject the null hypothesis

    
Wilcoxon rank sum test with continuity correction

data:  waiter and nowaiter
W = 36018000, p-value < 2.2e-16
alternative hypothesis: true location shift is greater than 0

  • 16.25% values in the group with Waiter Service are larger than the values in the group without it


Cliff's Delta

delta estimate: 0.1625034 (small)
95 percent confidence interval:
      inf       sup 
0.1447961 0.1801067

Answers

  • p-value < 2.2e-16 in Wilcoxon–Mann–Whitney test leads to the answer of primary question:
    Yes, the businesses with Waiter service tends to have larger number of Yelp tips per business than businesses without Waiter service.

  • Cliff's delta 0.1625034 tells us that
    impact of having a Waiter Service on the number of Yelp tips per business is small.