Kelly wants to examine the relationship between stress and eating when someone is on a diet. She recruits an equal number of male and female participants, who provide consent to complete a questionnaire about their eating habits, their typical mood, and their overall anxiety levels. Kelly ensures half of her male participants and half of her female participants are on a diet and the other half are not. After the questionnaire, all participants are randomly assigned to complete one of two tasks. Half of the participants solve a difficult math problem in front of a group of math professors within a certain time limit. The other participants solve a simple arithmetic problem in a waiting area alone, with no time limit. After they perform the task, all participants are asked to complete one more questionnaire about their stress level while sitting next to a box of Timbits. Kelly tells the participants to help themselves to the Timbits, and secretly counts how many Timbits the participant actually eats. Explain independent, dependent and what study is this