Researchers are interested in the effectiveness of a particular treatment for insomnia.

Researchers are interested in the effectiveness of a particular treatment for insomnia. Fifty insomnia sufferers who responded to a newspaper ad are contacted, and each is given a pill with instructions to take it before going to sleep that night. The pill actually contains milk powder (a placebo). The participants are randomly assigned to receive one of two sets of instructions about the pill. One half of the participants are told that the pill will make them feel "sleepy," and the other half are told that the pill will make them feel "awake and alert." The next day the participants return to the lab and are asked to indicate how long it took them to fall asleep after taking the pill. The individuals who were told that the pill would make them feel sleepy reported that they fell asleep faster than the participants who were told the pill would make them feel alert. Identify the independent and dependent variables. Indicate the number of levels in the independent variable and describe each level. Indicate whether the research used a between-participants or a within-participants research design and explain how you concluded which type of design was used. Suppose an ANOVA was conducted. Briefly explain what it would mean if the F was significant.