Dataset 1: Melatonin is a hormone that regulates sleep and can be bought as an over-the-counter supplement (usually to combat insomnia). An experiment ran by UCB tested college students to see how different dosages of melatonin supplements affect sleep. The researchers tested different levels of doses (1 mg, 2.5 mg, and 5 mg) and had a control. Does the dosage of melatonin improve sleep?

Describe the null hypothesis in words and in means