Tanvi works at a start-up company and wants to reduce stress in the workplace. She believes that installing aromatherapy diffusers in her coworkers' offices will help.
To test this, she chooses 20 coworkers and randomly assigns them to two equal
groups. She installs aromatherapy diffusers in the first group's offices and does
nothing in the second group's. At the end of one week, she has all 20 of the
coworkers indicate their stress levels on a scale of 1 (lowest) to 10 (highest).
Stress levels of coworkers with aromatherapy
5 2 7 2 7
4 2 2 2 5
Mean: 3.8
Stress levels of coworkers without aromatherapy
4 6
9
6
8 8 7 3 9
Mean: 6.4
How much lower is the average for the treatment group than the average for the
control group