1. Eric is interested in investigating the relationship between "happiness" and "helping behavior". He proposes to send the self-administration questionnaire to his friends for data collection. a. What is the data collection technique used in Eric's study? Please state ONE advantage and ONE disadvantage for this technique (3 marks) b. Which type of relationship is expected to find in Eric's study (correlation or causation)? Suggest the possible result of this study. How will you interpret the result? (3 marks)