An article titled “Are People More Aggressive When They Are Worse Off or Better Off Than Others?” published in Social Psychological and Personality Science (November 2012) reported on an experiment where researchers told the subjects in the study that they were interested in impression formation. The 72 French female college students who agreed to participate were asked to fill out a food preference survey on different foods such as dairy, spicy, sweet, salty, fruits, etc., rating each 1–21 with 1 being strongly dislike and 21 being strongly like. Each subject also wrote an essay on a particularly nice day in their life. Finally, they all participated in an illusory conjunction test where they were shown patterns of simple shapes for 70 milliseconds and they had to decide whether the dollar sign symbol was present or absent.

The subjects were told that all of these instruments were going to be used with a female partner to form impressions of them. The partner is fictitious in the study. The students were then all told they received 65% correct on their illusory conjunction test. Each was then randomly told one of three things about their partner’s score: The downward feedback group was told their partner scored 50% correct, the upward feedback group was told their partner scored 80% correct, and the control group was told they couldn’t provide feedback about their partner’s score due to a computer error. Then they received their own essay back which had been negatively rated by their partner, including a hand-written comment of “Poor writing, middle school level.” They also received their partner’s food likes/ dislikes with salty and spicy both rated as a 3. Next the students were told they had been randomly assigned to taste a sweet drink prepared by their partner and they were to prepare a tomato juice drink for their partner. They were told they could add salt and Tabasco sauce to the drink if they wished. They tasted a small sample of the drink before sending it to their partner. Then they tasted a drink of water sweetened with glucose which was prepared by their partner.

A statistic was constructed based on the amount of Tabasco sauce added and salt added to the tomato drink as a measurement of aggression.

Research question: Researchers wondered whether there would be any differences in the level of aggression between the downward feedback (thinking their partners scored less than them), the upward feedback (thinking their partners scored more than them), and the control feedback, in the population.

Question:

1. Calculate the MAD by hand for these data. Show your work.

2. Calculate the p-value.

3. Given the results of your analysis, provide an overall conclusion in context. Please include a generalization statement. Refer to the parameter and be very clear what you can claim about the population means.