basketball coach asks half his players to stretch before each game; the other players do not stretch. After a month of games, she analyzes their playing stats. She concludes the stretching helped improve their performance on the court. How can the coach test the means to be sure the results not likely to happen by chance?. .
The best way would be to now test the other group while the group that first stretched doesn't stretch in the coming period of time. She would have to change the people who stretch so as to see the new results for those new people.
