A Manufacturer of Tennis Rackets Has Designed a New Racket

Question 72

A manufacturer of tennis rackets has designed a new racket and would like to compare it to their previous design.They design an experiment as follows.They will obtain 100 volunteer tennis players.Volunteers will be randomly assigned to one of two groups.Group 1 will use the company's previous racket first and the new racket second.Group 2 will use the company's new racket first and the previous racket second.Each player will serve 100 times with each racket.The percentage of good serves with the two rackets will then be compared.The experiment is double blind.If the group of volunteers consists of 60 professional tennis players and 40 beginners,explain why blocking by tennis level would be important.