Question

1. A researcher wants to determine if frustration increases one’s level of aggression and randomly selects two groups of subjects from a class of 80 students. The experimental group (n1 = 40) will have to solve a frustrating puzzle, while the control group (n2 = 40) will take a 1-hour break. After one hour, the researcher measures the level of the students’ aggression using a short survey. The calculated mean of aggression for the experimental sample is 4.0 (std. deviation = 2.0) and for the control group the mean of aggression is 3.0 (std. deviation =  1.5).         (12 points)

1. Formulate the null and the alternative (research) hypotheses      
2. Test the null hypothesis [using the appropriate statistic] and reach a statistical conclusion [i.e., do you reject, or do you fail to reject the null hypothesis?]
3. Interpret your findings [i.e., if you reject (or not) H₀, what does this mean?]. Did having to solve the puzzle increase one’s level of aggression

Answer 1