Guilt in decision making. The effect of guilt emotion on how a decision-maker focuses on the problem was investigated in the Journal of Behavioral Decision Making (January 2007). A total of 155 volunteer students participated in the experiment, where each was randomly assigned to one of three emotional states (guilt, anger, or neutral) through a reading/writing task. Immediately after the task, the students were presented with a decision problem (e.g., whether or not to spend money on repairing a very old car). The researchers found that a higher proportion of students in the guilty-state group chose not to repair the car than those in the neutral-state and anger-state groups.

(a) Identify the population, sample, and variables measured for this study.

(b) What inference was made by the researcher?